linux/sound/usb/card.c

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/*
* (Tentative) USB Audio Driver for ALSA
*
* Copyright (c) 2002 by Takashi Iwai <tiwai@suse.de>
*
* Many codes borrowed from audio.c by
* Alan Cox (alan@lxorguk.ukuu.org.uk)
* Thomas Sailer (sailer@ife.ee.ethz.ch)
*
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*
* NOTES:
*
* - the linked URBs would be preferred but not used so far because of
* the instability of unlinking.
* - type II is not supported properly. there is no device which supports
* this type *correctly*. SB extigy looks as if it supports, but it's
* indeed an AC3 stream packed in SPDIF frames (i.e. no real AC3 stream).
*/
#include <linux/bitops.h>
#include <linux/init.h>
#include <linux/list.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/ctype.h>
#include <linux/usb.h>
#include <linux/moduleparam.h>
#include <linux/mutex.h>
#include <linux/usb/audio.h>
#include <linux/usb/audio-v2.h>
#include <linux/module.h>
#include <sound/control.h>
#include <sound/core.h>
#include <sound/info.h>
#include <sound/pcm.h>
#include <sound/pcm_params.h>
#include <sound/initval.h>
#include "usbaudio.h"
#include "card.h"
#include "midi.h"
#include "mixer.h"
#include "proc.h"
#include "quirks.h"
#include "endpoint.h"
#include "helper.h"
#include "debug.h"
#include "pcm.h"
#include "format.h"
#include "power.h"
#include "stream.h"
MODULE_AUTHOR("Takashi Iwai <tiwai@suse.de>");
MODULE_DESCRIPTION("USB Audio");
MODULE_LICENSE("GPL");
MODULE_SUPPORTED_DEVICE("{{Generic,USB Audio}}");
static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX; /* Index 0-MAX */
static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR; /* ID for this card */
static bool enable[SNDRV_CARDS] = SNDRV_DEFAULT_ENABLE_PNP;/* Enable this card */
/* Vendor/product IDs for this card */
static int vid[SNDRV_CARDS] = { [0 ... (SNDRV_CARDS-1)] = -1 };
static int pid[SNDRV_CARDS] = { [0 ... (SNDRV_CARDS-1)] = -1 };
static int device_setup[SNDRV_CARDS]; /* device parameter for this card */
static bool ignore_ctl_error;
static bool autoclock = true;
module_param_array(index, int, NULL, 0444);
MODULE_PARM_DESC(index, "Index value for the USB audio adapter.");
module_param_array(id, charp, NULL, 0444);
MODULE_PARM_DESC(id, "ID string for the USB audio adapter.");
module_param_array(enable, bool, NULL, 0444);
MODULE_PARM_DESC(enable, "Enable USB audio adapter.");
module_param_array(vid, int, NULL, 0444);
MODULE_PARM_DESC(vid, "Vendor ID for the USB audio device.");
module_param_array(pid, int, NULL, 0444);
MODULE_PARM_DESC(pid, "Product ID for the USB audio device.");
module_param_array(device_setup, int, NULL, 0444);
MODULE_PARM_DESC(device_setup, "Specific device setup (if needed).");
module_param(ignore_ctl_error, bool, 0444);
MODULE_PARM_DESC(ignore_ctl_error,
"Ignore errors from USB controller for mixer interfaces.");
module_param(autoclock, bool, 0444);
MODULE_PARM_DESC(autoclock, "Enable auto-clock selection for UAC2 devices (default: yes).");
/*
* we keep the snd_usb_audio_t instances by ourselves for merging
* the all interfaces on the same card as one sound device.
*/
static DEFINE_MUTEX(register_mutex);
static struct snd_usb_audio *usb_chip[SNDRV_CARDS];
static struct usb_driver usb_audio_driver;
/*
* disconnect streams
* called from usb_audio_disconnect()
*/
static void snd_usb_stream_disconnect(struct snd_usb_stream *as)
{
int idx;
struct snd_usb_substream *subs;
for (idx = 0; idx < 2; idx++) {
subs = &as->substream[idx];
if (!subs->num_formats)
continue;
subs->interface = -1;
subs->data_endpoint = NULL;
subs->sync_endpoint = NULL;
}
}
static int snd_usb_create_stream(struct snd_usb_audio *chip, int ctrlif, int interface)
{
struct usb_device *dev = chip->dev;
struct usb_host_interface *alts;
struct usb_interface_descriptor *altsd;
struct usb_interface *iface = usb_ifnum_to_if(dev, interface);
if (!iface) {
dev_err(&dev->dev, "%u:%d : does not exist\n",
ctrlif, interface);
return -EINVAL;
}
alts = &iface->altsetting[0];
altsd = get_iface_desc(alts);
/*
* Android with both accessory and audio interfaces enabled gets the
* interface numbers wrong.
*/
if ((chip->usb_id == USB_ID(0x18d1, 0x2d04) ||
chip->usb_id == USB_ID(0x18d1, 0x2d05)) &&
interface == 0 &&
altsd->bInterfaceClass == USB_CLASS_VENDOR_SPEC &&
altsd->bInterfaceSubClass == USB_SUBCLASS_VENDOR_SPEC) {
interface = 2;
iface = usb_ifnum_to_if(dev, interface);
if (!iface)
return -EINVAL;
alts = &iface->altsetting[0];
altsd = get_iface_desc(alts);
}
if (usb_interface_claimed(iface)) {
dev_dbg(&dev->dev, "%d:%d: skipping, already claimed\n",
ctrlif, interface);
return -EINVAL;
}
if ((altsd->bInterfaceClass == USB_CLASS_AUDIO ||
altsd->bInterfaceClass == USB_CLASS_VENDOR_SPEC) &&
altsd->bInterfaceSubClass == USB_SUBCLASS_MIDISTREAMING) {
int err = snd_usbmidi_create(chip->card, iface,
&chip->midi_list, NULL);
if (err < 0) {
dev_err(&dev->dev,
"%u:%d: cannot create sequencer device\n",
ctrlif, interface);
return -EINVAL;
}
usb_driver_claim_interface(&usb_audio_driver, iface, (void *)-1L);
return 0;
}
if ((altsd->bInterfaceClass != USB_CLASS_AUDIO &&
altsd->bInterfaceClass != USB_CLASS_VENDOR_SPEC) ||
altsd->bInterfaceSubClass != USB_SUBCLASS_AUDIOSTREAMING) {
dev_dbg(&dev->dev,
"%u:%d: skipping non-supported interface %d\n",
ctrlif, interface, altsd->bInterfaceClass);
/* skip non-supported classes */
return -EINVAL;
}
if (snd_usb_get_speed(dev) == USB_SPEED_LOW) {
dev_err(&dev->dev, "low speed audio streaming not supported\n");
return -EINVAL;
}
if (! snd_usb_parse_audio_interface(chip, interface)) {
usb_set_interface(dev, interface, 0); /* reset the current interface */
usb_driver_claim_interface(&usb_audio_driver, iface, (void *)-1L);
return -EINVAL;
}
return 0;
}
/*
* parse audio control descriptor and create pcm/midi streams
*/
static int snd_usb_create_streams(struct snd_usb_audio *chip, int ctrlif)
{
struct usb_device *dev = chip->dev;
struct usb_host_interface *host_iface;
struct usb_interface_descriptor *altsd;
void *control_header;
int i, protocol;
/* find audiocontrol interface */
host_iface = &usb_ifnum_to_if(dev, ctrlif)->altsetting[0];
control_header = snd_usb_find_csint_desc(host_iface->extra,
host_iface->extralen,
NULL, UAC_HEADER);
altsd = get_iface_desc(host_iface);
protocol = altsd->bInterfaceProtocol;
if (!control_header) {
dev_err(&dev->dev, "cannot find UAC_HEADER\n");
return -EINVAL;
}
switch (protocol) {
default:
dev_warn(&dev->dev,
"unknown interface protocol %#02x, assuming v1\n",
protocol);
/* fall through */
case UAC_VERSION_1: {
struct uac1_ac_header_descriptor *h1 = control_header;
if (!h1->bInCollection) {
dev_info(&dev->dev, "skipping empty audio interface (v1)\n");
return -EINVAL;
}
if (h1->bLength < sizeof(*h1) + h1->bInCollection) {
dev_err(&dev->dev, "invalid UAC_HEADER (v1)\n");
return -EINVAL;
}
for (i = 0; i < h1->bInCollection; i++)
snd_usb_create_stream(chip, ctrlif, h1->baInterfaceNr[i]);
break;
}
case UAC_VERSION_2: {
struct usb_interface_assoc_descriptor *assoc =
usb_ifnum_to_if(dev, ctrlif)->intf_assoc;
if (!assoc) {
/*
* Firmware writers cannot count to three. So to find
* the IAD on the NuForce UDH-100, also check the next
* interface.
*/
struct usb_interface *iface =
usb_ifnum_to_if(dev, ctrlif + 1);
if (iface &&
iface->intf_assoc &&
iface->intf_assoc->bFunctionClass == USB_CLASS_AUDIO &&
iface->intf_assoc->bFunctionProtocol == UAC_VERSION_2)
assoc = iface->intf_assoc;
}
if (!assoc) {
dev_err(&dev->dev, "Audio class v2 interfaces need an interface association\n");
return -EINVAL;
}
for (i = 0; i < assoc->bInterfaceCount; i++) {
int intf = assoc->bFirstInterface + i;
if (intf != ctrlif)
snd_usb_create_stream(chip, ctrlif, intf);
}
break;
}
}
return 0;
}
/*
* free the chip instance
*
* here we have to do not much, since pcm and controls are already freed
*
*/
static int snd_usb_audio_free(struct snd_usb_audio *chip)
{
struct snd_usb_endpoint *ep, *n;
list_for_each_entry_safe(ep, n, &chip->ep_list, list)
snd_usb_endpoint_free(ep);
mutex_destroy(&chip->mutex);
kfree(chip);
return 0;
}
static int snd_usb_audio_dev_free(struct snd_device *device)
{
struct snd_usb_audio *chip = device->device_data;
return snd_usb_audio_free(chip);
}
/*
* create a chip instance and set its names.
*/
static int snd_usb_audio_create(struct usb_interface *intf,
struct usb_device *dev, int idx,
const struct snd_usb_audio_quirk *quirk,
struct snd_usb_audio **rchip)
{
struct snd_card *card;
struct snd_usb_audio *chip;
int err, len;
char component[14];
static struct snd_device_ops ops = {
.dev_free = snd_usb_audio_dev_free,
};
*rchip = NULL;
switch (snd_usb_get_speed(dev)) {
case USB_SPEED_LOW:
case USB_SPEED_FULL:
case USB_SPEED_HIGH:
case USB_SPEED_WIRELESS:
case USB_SPEED_SUPER:
break;
default:
dev_err(&dev->dev, "unknown device speed %d\n", snd_usb_get_speed(dev));
return -ENXIO;
}
err = snd_card_new(&intf->dev, index[idx], id[idx], THIS_MODULE,
0, &card);
if (err < 0) {
dev_err(&dev->dev, "cannot create card instance %d\n", idx);
return err;
}
chip = kzalloc(sizeof(*chip), GFP_KERNEL);
if (! chip) {
snd_card_free(card);
return -ENOMEM;
}
mutex_init(&chip->mutex);
ALSA: usb-audio: Avoid nested autoresume calls After the recent fix of runtime PM for USB-audio driver, we got a lockdep warning like: ============================================= [ INFO: possible recursive locking detected ] 4.2.0-rc8+ #61 Not tainted --------------------------------------------- pulseaudio/980 is trying to acquire lock: (&chip->shutdown_rwsem){.+.+.+}, at: [<ffffffffa0355dac>] snd_usb_autoresume+0x1d/0x52 [snd_usb_audio] but task is already holding lock: (&chip->shutdown_rwsem){.+.+.+}, at: [<ffffffffa0355dac>] snd_usb_autoresume+0x1d/0x52 [snd_usb_audio] This comes from snd_usb_autoresume() invoking down_read() and it's used in a nested way. Although it's basically safe, per se (as these are read locks), it's better to reduce such spurious warnings. The read lock is needed to guarantee the execution of "shutdown" (cleanup at disconnection) task after all concurrent tasks are finished. This can be implemented in another better way. Also, the current check of chip->in_pm isn't good enough for protecting the racy execution of multiple auto-resumes. This patch rewrites the logic of snd_usb_autoresume() & co; namely, - The recursive call of autopm is avoided by the new refcount, chip->active. The chip->in_pm flag is removed accordingly. - Instead of rwsem, another refcount, chip->usage_count, is introduced for tracking the period to delay the shutdown procedure. At the last clear of this refcount, wake_up() to the shutdown waiter is called. - The shutdown flag is replaced with shutdown atomic count; this is for reducing the lock. - Two new helpers are introduced to simplify the management of these refcounts; snd_usb_lock_shutdown() increases the usage_count, checks the shutdown state, and does autoresume. snd_usb_unlock_shutdown() does the opposite. Most of mixer and other codes just need this, and simply returns an error if it receives an error from lock. Fixes: 9003ebb13f61 ('ALSA: usb-audio: Fix runtime PM unbalance') Reported-and-tested-by: Alexnader Kuleshov <kuleshovmail@gmail.com> Signed-off-by: Takashi Iwai <tiwai@suse.de>
2015-08-25 14:09:00 +00:00
init_waitqueue_head(&chip->shutdown_wait);
chip->index = idx;
chip->dev = dev;
chip->card = card;
chip->setup = device_setup[idx];
chip->autoclock = autoclock;
atomic_set(&chip->active, 1); /* avoid autopm during probing */
ALSA: usb-audio: Avoid nested autoresume calls After the recent fix of runtime PM for USB-audio driver, we got a lockdep warning like: ============================================= [ INFO: possible recursive locking detected ] 4.2.0-rc8+ #61 Not tainted --------------------------------------------- pulseaudio/980 is trying to acquire lock: (&chip->shutdown_rwsem){.+.+.+}, at: [<ffffffffa0355dac>] snd_usb_autoresume+0x1d/0x52 [snd_usb_audio] but task is already holding lock: (&chip->shutdown_rwsem){.+.+.+}, at: [<ffffffffa0355dac>] snd_usb_autoresume+0x1d/0x52 [snd_usb_audio] This comes from snd_usb_autoresume() invoking down_read() and it's used in a nested way. Although it's basically safe, per se (as these are read locks), it's better to reduce such spurious warnings. The read lock is needed to guarantee the execution of "shutdown" (cleanup at disconnection) task after all concurrent tasks are finished. This can be implemented in another better way. Also, the current check of chip->in_pm isn't good enough for protecting the racy execution of multiple auto-resumes. This patch rewrites the logic of snd_usb_autoresume() & co; namely, - The recursive call of autopm is avoided by the new refcount, chip->active. The chip->in_pm flag is removed accordingly. - Instead of rwsem, another refcount, chip->usage_count, is introduced for tracking the period to delay the shutdown procedure. At the last clear of this refcount, wake_up() to the shutdown waiter is called. - The shutdown flag is replaced with shutdown atomic count; this is for reducing the lock. - Two new helpers are introduced to simplify the management of these refcounts; snd_usb_lock_shutdown() increases the usage_count, checks the shutdown state, and does autoresume. snd_usb_unlock_shutdown() does the opposite. Most of mixer and other codes just need this, and simply returns an error if it receives an error from lock. Fixes: 9003ebb13f61 ('ALSA: usb-audio: Fix runtime PM unbalance') Reported-and-tested-by: Alexnader Kuleshov <kuleshovmail@gmail.com> Signed-off-by: Takashi Iwai <tiwai@suse.de>
2015-08-25 14:09:00 +00:00
atomic_set(&chip->usage_count, 0);
atomic_set(&chip->shutdown, 0);
chip->usb_id = USB_ID(le16_to_cpu(dev->descriptor.idVendor),
le16_to_cpu(dev->descriptor.idProduct));
INIT_LIST_HEAD(&chip->pcm_list);
INIT_LIST_HEAD(&chip->ep_list);
INIT_LIST_HEAD(&chip->midi_list);
INIT_LIST_HEAD(&chip->mixer_list);
if ((err = snd_device_new(card, SNDRV_DEV_LOWLEVEL, chip, &ops)) < 0) {
snd_usb_audio_free(chip);
snd_card_free(card);
return err;
}
strcpy(card->driver, "USB-Audio");
sprintf(component, "USB%04x:%04x",
USB_ID_VENDOR(chip->usb_id), USB_ID_PRODUCT(chip->usb_id));
snd_component_add(card, component);
/* retrieve the device string as shortname */
if (quirk && quirk->product_name && *quirk->product_name) {
strlcpy(card->shortname, quirk->product_name, sizeof(card->shortname));
} else {
if (!dev->descriptor.iProduct ||
usb_string(dev, dev->descriptor.iProduct,
card->shortname, sizeof(card->shortname)) <= 0) {
/* no name available from anywhere, so use ID */
sprintf(card->shortname, "USB Device %#04x:%#04x",
USB_ID_VENDOR(chip->usb_id),
USB_ID_PRODUCT(chip->usb_id));
}
}
strim(card->shortname);
/* retrieve the vendor and device strings as longname */
if (quirk && quirk->vendor_name && *quirk->vendor_name) {
len = strlcpy(card->longname, quirk->vendor_name, sizeof(card->longname));
} else {
if (dev->descriptor.iManufacturer)
len = usb_string(dev, dev->descriptor.iManufacturer,
card->longname, sizeof(card->longname));
else
len = 0;
/* we don't really care if there isn't any vendor string */
}
if (len > 0) {
strim(card->longname);
if (*card->longname)
strlcat(card->longname, " ", sizeof(card->longname));
}
strlcat(card->longname, card->shortname, sizeof(card->longname));
len = strlcat(card->longname, " at ", sizeof(card->longname));
if (len < sizeof(card->longname))
usb_make_path(dev, card->longname + len, sizeof(card->longname) - len);
switch (snd_usb_get_speed(dev)) {
case USB_SPEED_LOW:
strlcat(card->longname, ", low speed", sizeof(card->longname));
break;
case USB_SPEED_FULL:
strlcat(card->longname, ", full speed", sizeof(card->longname));
break;
case USB_SPEED_HIGH:
strlcat(card->longname, ", high speed", sizeof(card->longname));
break;
case USB_SPEED_SUPER:
strlcat(card->longname, ", super speed", sizeof(card->longname));
break;
default:
break;
}
snd_usb_audio_create_proc(chip);
*rchip = chip;
return 0;
}
/*
* probe the active usb device
*
* note that this can be called multiple times per a device, when it
* includes multiple audio control interfaces.
*
* thus we check the usb device pointer and creates the card instance
* only at the first time. the successive calls of this function will
* append the pcm interface to the corresponding card.
*/
static int usb_audio_probe(struct usb_interface *intf,
const struct usb_device_id *usb_id)
{
struct usb_device *dev = interface_to_usbdev(intf);
const struct snd_usb_audio_quirk *quirk =
(const struct snd_usb_audio_quirk *)usb_id->driver_info;
struct snd_usb_audio *chip;
int i, err;
struct usb_host_interface *alts;
int ifnum;
u32 id;
alts = &intf->altsetting[0];
ifnum = get_iface_desc(alts)->bInterfaceNumber;
id = USB_ID(le16_to_cpu(dev->descriptor.idVendor),
le16_to_cpu(dev->descriptor.idProduct));
if (quirk && quirk->ifnum >= 0 && ifnum != quirk->ifnum)
return -ENXIO;
err = snd_usb_apply_boot_quirk(dev, intf, quirk);
if (err < 0)
return err;
/*
* found a config. now register to ALSA
*/
/* check whether it's already registered */
chip = NULL;
mutex_lock(&register_mutex);
for (i = 0; i < SNDRV_CARDS; i++) {
if (usb_chip[i] && usb_chip[i]->dev == dev) {
ALSA: usb-audio: Avoid nested autoresume calls After the recent fix of runtime PM for USB-audio driver, we got a lockdep warning like: ============================================= [ INFO: possible recursive locking detected ] 4.2.0-rc8+ #61 Not tainted --------------------------------------------- pulseaudio/980 is trying to acquire lock: (&chip->shutdown_rwsem){.+.+.+}, at: [<ffffffffa0355dac>] snd_usb_autoresume+0x1d/0x52 [snd_usb_audio] but task is already holding lock: (&chip->shutdown_rwsem){.+.+.+}, at: [<ffffffffa0355dac>] snd_usb_autoresume+0x1d/0x52 [snd_usb_audio] This comes from snd_usb_autoresume() invoking down_read() and it's used in a nested way. Although it's basically safe, per se (as these are read locks), it's better to reduce such spurious warnings. The read lock is needed to guarantee the execution of "shutdown" (cleanup at disconnection) task after all concurrent tasks are finished. This can be implemented in another better way. Also, the current check of chip->in_pm isn't good enough for protecting the racy execution of multiple auto-resumes. This patch rewrites the logic of snd_usb_autoresume() & co; namely, - The recursive call of autopm is avoided by the new refcount, chip->active. The chip->in_pm flag is removed accordingly. - Instead of rwsem, another refcount, chip->usage_count, is introduced for tracking the period to delay the shutdown procedure. At the last clear of this refcount, wake_up() to the shutdown waiter is called. - The shutdown flag is replaced with shutdown atomic count; this is for reducing the lock. - Two new helpers are introduced to simplify the management of these refcounts; snd_usb_lock_shutdown() increases the usage_count, checks the shutdown state, and does autoresume. snd_usb_unlock_shutdown() does the opposite. Most of mixer and other codes just need this, and simply returns an error if it receives an error from lock. Fixes: 9003ebb13f61 ('ALSA: usb-audio: Fix runtime PM unbalance') Reported-and-tested-by: Alexnader Kuleshov <kuleshovmail@gmail.com> Signed-off-by: Takashi Iwai <tiwai@suse.de>
2015-08-25 14:09:00 +00:00
if (atomic_read(&usb_chip[i]->shutdown)) {
dev_err(&dev->dev, "USB device is in the shutdown state, cannot create a card instance\n");
err = -EIO;
goto __error;
}
chip = usb_chip[i];
atomic_inc(&chip->active); /* avoid autopm */
break;
}
}
if (! chip) {
/* it's a fresh one.
* now look for an empty slot and create a new card instance
*/
for (i = 0; i < SNDRV_CARDS; i++)
if (enable[i] && ! usb_chip[i] &&
(vid[i] == -1 || vid[i] == USB_ID_VENDOR(id)) &&
(pid[i] == -1 || pid[i] == USB_ID_PRODUCT(id))) {
err = snd_usb_audio_create(intf, dev, i, quirk,
&chip);
if (err < 0)
goto __error;
chip->pm_intf = intf;
break;
}
if (!chip) {
dev_err(&dev->dev, "no available usb audio device\n");
err = -ENODEV;
goto __error;
}
}
/*
* For devices with more than one control interface, we assume the
* first contains the audio controls. We might need a more specific
* check here in the future.
*/
if (!chip->ctrl_intf)
chip->ctrl_intf = alts;
chip->txfr_quirk = 0;
err = 1; /* continue */
if (quirk && quirk->ifnum != QUIRK_NO_INTERFACE) {
/* need some special handlings */
err = snd_usb_create_quirk(chip, intf, &usb_audio_driver, quirk);
if (err < 0)
goto __error;
}
if (err > 0) {
/* create normal USB audio interfaces */
err = snd_usb_create_streams(chip, ifnum);
if (err < 0)
goto __error;
err = snd_usb_create_mixer(chip, ifnum, ignore_ctl_error);
if (err < 0)
goto __error;
}
/* we are allowed to call snd_card_register() many times */
err = snd_card_register(chip->card);
if (err < 0)
goto __error;
usb_chip[chip->index] = chip;
chip->num_interfaces++;
usb_set_intfdata(intf, chip);
atomic_dec(&chip->active);
mutex_unlock(&register_mutex);
return 0;
__error:
if (chip) {
if (!chip->num_interfaces)
snd_card_free(chip->card);
atomic_dec(&chip->active);
}
mutex_unlock(&register_mutex);
return err;
}
/*
* we need to take care of counter, since disconnection can be called also
* many times as well as usb_audio_probe().
*/
static void usb_audio_disconnect(struct usb_interface *intf)
{
struct snd_usb_audio *chip = usb_get_intfdata(intf);
struct snd_card *card;
struct list_head *p;
if (chip == (void *)-1L)
return;
card = chip->card;
mutex_lock(&register_mutex);
ALSA: usb-audio: Avoid nested autoresume calls After the recent fix of runtime PM for USB-audio driver, we got a lockdep warning like: ============================================= [ INFO: possible recursive locking detected ] 4.2.0-rc8+ #61 Not tainted --------------------------------------------- pulseaudio/980 is trying to acquire lock: (&chip->shutdown_rwsem){.+.+.+}, at: [<ffffffffa0355dac>] snd_usb_autoresume+0x1d/0x52 [snd_usb_audio] but task is already holding lock: (&chip->shutdown_rwsem){.+.+.+}, at: [<ffffffffa0355dac>] snd_usb_autoresume+0x1d/0x52 [snd_usb_audio] This comes from snd_usb_autoresume() invoking down_read() and it's used in a nested way. Although it's basically safe, per se (as these are read locks), it's better to reduce such spurious warnings. The read lock is needed to guarantee the execution of "shutdown" (cleanup at disconnection) task after all concurrent tasks are finished. This can be implemented in another better way. Also, the current check of chip->in_pm isn't good enough for protecting the racy execution of multiple auto-resumes. This patch rewrites the logic of snd_usb_autoresume() & co; namely, - The recursive call of autopm is avoided by the new refcount, chip->active. The chip->in_pm flag is removed accordingly. - Instead of rwsem, another refcount, chip->usage_count, is introduced for tracking the period to delay the shutdown procedure. At the last clear of this refcount, wake_up() to the shutdown waiter is called. - The shutdown flag is replaced with shutdown atomic count; this is for reducing the lock. - Two new helpers are introduced to simplify the management of these refcounts; snd_usb_lock_shutdown() increases the usage_count, checks the shutdown state, and does autoresume. snd_usb_unlock_shutdown() does the opposite. Most of mixer and other codes just need this, and simply returns an error if it receives an error from lock. Fixes: 9003ebb13f61 ('ALSA: usb-audio: Fix runtime PM unbalance') Reported-and-tested-by: Alexnader Kuleshov <kuleshovmail@gmail.com> Signed-off-by: Takashi Iwai <tiwai@suse.de>
2015-08-25 14:09:00 +00:00
if (atomic_inc_return(&chip->shutdown) == 1) {
struct snd_usb_stream *as;
struct snd_usb_endpoint *ep;
struct usb_mixer_interface *mixer;
ALSA: usb-audio: Avoid nested autoresume calls After the recent fix of runtime PM for USB-audio driver, we got a lockdep warning like: ============================================= [ INFO: possible recursive locking detected ] 4.2.0-rc8+ #61 Not tainted --------------------------------------------- pulseaudio/980 is trying to acquire lock: (&chip->shutdown_rwsem){.+.+.+}, at: [<ffffffffa0355dac>] snd_usb_autoresume+0x1d/0x52 [snd_usb_audio] but task is already holding lock: (&chip->shutdown_rwsem){.+.+.+}, at: [<ffffffffa0355dac>] snd_usb_autoresume+0x1d/0x52 [snd_usb_audio] This comes from snd_usb_autoresume() invoking down_read() and it's used in a nested way. Although it's basically safe, per se (as these are read locks), it's better to reduce such spurious warnings. The read lock is needed to guarantee the execution of "shutdown" (cleanup at disconnection) task after all concurrent tasks are finished. This can be implemented in another better way. Also, the current check of chip->in_pm isn't good enough for protecting the racy execution of multiple auto-resumes. This patch rewrites the logic of snd_usb_autoresume() & co; namely, - The recursive call of autopm is avoided by the new refcount, chip->active. The chip->in_pm flag is removed accordingly. - Instead of rwsem, another refcount, chip->usage_count, is introduced for tracking the period to delay the shutdown procedure. At the last clear of this refcount, wake_up() to the shutdown waiter is called. - The shutdown flag is replaced with shutdown atomic count; this is for reducing the lock. - Two new helpers are introduced to simplify the management of these refcounts; snd_usb_lock_shutdown() increases the usage_count, checks the shutdown state, and does autoresume. snd_usb_unlock_shutdown() does the opposite. Most of mixer and other codes just need this, and simply returns an error if it receives an error from lock. Fixes: 9003ebb13f61 ('ALSA: usb-audio: Fix runtime PM unbalance') Reported-and-tested-by: Alexnader Kuleshov <kuleshovmail@gmail.com> Signed-off-by: Takashi Iwai <tiwai@suse.de>
2015-08-25 14:09:00 +00:00
/* wait until all pending tasks done;
* they are protected by snd_usb_lock_shutdown()
*/
wait_event(chip->shutdown_wait,
!atomic_read(&chip->usage_count));
snd_card_disconnect(card);
/* release the pcm resources */
list_for_each_entry(as, &chip->pcm_list, list) {
snd_usb_stream_disconnect(as);
}
/* release the endpoint resources */
list_for_each_entry(ep, &chip->ep_list, list) {
snd_usb_endpoint_release(ep);
}
/* release the midi resources */
list_for_each(p, &chip->midi_list) {
snd_usbmidi_disconnect(p);
}
/* release mixer resources */
list_for_each_entry(mixer, &chip->mixer_list, list) {
snd_usb_mixer_disconnect(mixer);
}
ALSA: usb-audio: Fix device_del() sysfs warnings at disconnect Some USB-audio devices show weird sysfs warnings at disconnecting the devices, e.g. usb 1-3: USB disconnect, device number 3 ------------[ cut here ]------------ WARNING: CPU: 0 PID: 973 at fs/sysfs/group.c:216 device_del+0x39/0x180() sysfs group ffffffff8183df40 not found for kobject 'midiC1D0' Call Trace: [<ffffffff814a3e38>] ? dump_stack+0x49/0x71 [<ffffffff8103cb72>] ? warn_slowpath_common+0x82/0xb0 [<ffffffff8103cc55>] ? warn_slowpath_fmt+0x45/0x50 [<ffffffff813521e9>] ? device_del+0x39/0x180 [<ffffffff81352339>] ? device_unregister+0x9/0x20 [<ffffffff81352384>] ? device_destroy+0x34/0x40 [<ffffffffa00ba29f>] ? snd_unregister_device+0x7f/0xd0 [snd] [<ffffffffa025124e>] ? snd_rawmidi_dev_disconnect+0xce/0x100 [snd_rawmidi] [<ffffffffa00c0192>] ? snd_device_disconnect+0x62/0x90 [snd] [<ffffffffa00c025c>] ? snd_device_disconnect_all+0x3c/0x60 [snd] [<ffffffffa00bb574>] ? snd_card_disconnect+0x124/0x1a0 [snd] [<ffffffffa02e54e8>] ? usb_audio_disconnect+0x88/0x1c0 [snd_usb_audio] [<ffffffffa015260e>] ? usb_unbind_interface+0x5e/0x1b0 [usbcore] [<ffffffff813553e9>] ? __device_release_driver+0x79/0xf0 [<ffffffff81355485>] ? device_release_driver+0x25/0x40 [<ffffffff81354e11>] ? bus_remove_device+0xf1/0x130 [<ffffffff813522b9>] ? device_del+0x109/0x180 [<ffffffffa01501d5>] ? usb_disable_device+0x95/0x1f0 [usbcore] [<ffffffffa014634f>] ? usb_disconnect+0x8f/0x190 [usbcore] [<ffffffffa0149179>] ? hub_thread+0x539/0x13a0 [usbcore] [<ffffffff810669f5>] ? sched_clock_local+0x15/0x80 [<ffffffff81066c98>] ? sched_clock_cpu+0xb8/0xd0 [<ffffffff81070730>] ? bit_waitqueue+0xb0/0xb0 [<ffffffffa0148c40>] ? usb_port_resume+0x430/0x430 [usbcore] [<ffffffffa0148c40>] ? usb_port_resume+0x430/0x430 [usbcore] [<ffffffff8105973e>] ? kthread+0xce/0xf0 [<ffffffff81059670>] ? kthread_create_on_node+0x1c0/0x1c0 [<ffffffff814a8b7c>] ? ret_from_fork+0x7c/0xb0 [<ffffffff81059670>] ? kthread_create_on_node+0x1c0/0x1c0 ---[ end trace 40b1928d1136b91e ]--- This comes from the fact that usb-audio driver may receive the disconnect callback multiple times, per each usb interface. When a device has both audio and midi interfaces, it gets called twice, and currently the driver tries to release resources at the last call. At this point, the first parent interface has been already deleted, thus deleting a child of the first parent hits such a warning. For fixing this problem, we need to call snd_card_disconnect() and cancel pending operations at the very first disconnect while the release of the whole objects waits until the last disconnect call. Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=80931 Reported-and-tested-by: Tomas Gayoso <tgayoso@gmail.com> Reported-and-tested-by: Chris J Arges <chris.j.arges@canonical.com> Cc: <stable@vger.kernel.org> Signed-off-by: Takashi Iwai <tiwai@suse.de>
2014-11-05 14:08:49 +00:00
}
chip->num_interfaces--;
if (chip->num_interfaces <= 0) {
usb_chip[chip->index] = NULL;
mutex_unlock(&register_mutex);
snd_card_free_when_closed(card);
} else {
mutex_unlock(&register_mutex);
}
}
ALSA: usb-audio: Avoid nested autoresume calls After the recent fix of runtime PM for USB-audio driver, we got a lockdep warning like: ============================================= [ INFO: possible recursive locking detected ] 4.2.0-rc8+ #61 Not tainted --------------------------------------------- pulseaudio/980 is trying to acquire lock: (&chip->shutdown_rwsem){.+.+.+}, at: [<ffffffffa0355dac>] snd_usb_autoresume+0x1d/0x52 [snd_usb_audio] but task is already holding lock: (&chip->shutdown_rwsem){.+.+.+}, at: [<ffffffffa0355dac>] snd_usb_autoresume+0x1d/0x52 [snd_usb_audio] This comes from snd_usb_autoresume() invoking down_read() and it's used in a nested way. Although it's basically safe, per se (as these are read locks), it's better to reduce such spurious warnings. The read lock is needed to guarantee the execution of "shutdown" (cleanup at disconnection) task after all concurrent tasks are finished. This can be implemented in another better way. Also, the current check of chip->in_pm isn't good enough for protecting the racy execution of multiple auto-resumes. This patch rewrites the logic of snd_usb_autoresume() & co; namely, - The recursive call of autopm is avoided by the new refcount, chip->active. The chip->in_pm flag is removed accordingly. - Instead of rwsem, another refcount, chip->usage_count, is introduced for tracking the period to delay the shutdown procedure. At the last clear of this refcount, wake_up() to the shutdown waiter is called. - The shutdown flag is replaced with shutdown atomic count; this is for reducing the lock. - Two new helpers are introduced to simplify the management of these refcounts; snd_usb_lock_shutdown() increases the usage_count, checks the shutdown state, and does autoresume. snd_usb_unlock_shutdown() does the opposite. Most of mixer and other codes just need this, and simply returns an error if it receives an error from lock. Fixes: 9003ebb13f61 ('ALSA: usb-audio: Fix runtime PM unbalance') Reported-and-tested-by: Alexnader Kuleshov <kuleshovmail@gmail.com> Signed-off-by: Takashi Iwai <tiwai@suse.de>
2015-08-25 14:09:00 +00:00
/* lock the shutdown (disconnect) task and autoresume */
int snd_usb_lock_shutdown(struct snd_usb_audio *chip)
{
ALSA: usb-audio: Avoid nested autoresume calls After the recent fix of runtime PM for USB-audio driver, we got a lockdep warning like: ============================================= [ INFO: possible recursive locking detected ] 4.2.0-rc8+ #61 Not tainted --------------------------------------------- pulseaudio/980 is trying to acquire lock: (&chip->shutdown_rwsem){.+.+.+}, at: [<ffffffffa0355dac>] snd_usb_autoresume+0x1d/0x52 [snd_usb_audio] but task is already holding lock: (&chip->shutdown_rwsem){.+.+.+}, at: [<ffffffffa0355dac>] snd_usb_autoresume+0x1d/0x52 [snd_usb_audio] This comes from snd_usb_autoresume() invoking down_read() and it's used in a nested way. Although it's basically safe, per se (as these are read locks), it's better to reduce such spurious warnings. The read lock is needed to guarantee the execution of "shutdown" (cleanup at disconnection) task after all concurrent tasks are finished. This can be implemented in another better way. Also, the current check of chip->in_pm isn't good enough for protecting the racy execution of multiple auto-resumes. This patch rewrites the logic of snd_usb_autoresume() & co; namely, - The recursive call of autopm is avoided by the new refcount, chip->active. The chip->in_pm flag is removed accordingly. - Instead of rwsem, another refcount, chip->usage_count, is introduced for tracking the period to delay the shutdown procedure. At the last clear of this refcount, wake_up() to the shutdown waiter is called. - The shutdown flag is replaced with shutdown atomic count; this is for reducing the lock. - Two new helpers are introduced to simplify the management of these refcounts; snd_usb_lock_shutdown() increases the usage_count, checks the shutdown state, and does autoresume. snd_usb_unlock_shutdown() does the opposite. Most of mixer and other codes just need this, and simply returns an error if it receives an error from lock. Fixes: 9003ebb13f61 ('ALSA: usb-audio: Fix runtime PM unbalance') Reported-and-tested-by: Alexnader Kuleshov <kuleshovmail@gmail.com> Signed-off-by: Takashi Iwai <tiwai@suse.de>
2015-08-25 14:09:00 +00:00
int err;
ALSA: usb-audio: Avoid nested autoresume calls After the recent fix of runtime PM for USB-audio driver, we got a lockdep warning like: ============================================= [ INFO: possible recursive locking detected ] 4.2.0-rc8+ #61 Not tainted --------------------------------------------- pulseaudio/980 is trying to acquire lock: (&chip->shutdown_rwsem){.+.+.+}, at: [<ffffffffa0355dac>] snd_usb_autoresume+0x1d/0x52 [snd_usb_audio] but task is already holding lock: (&chip->shutdown_rwsem){.+.+.+}, at: [<ffffffffa0355dac>] snd_usb_autoresume+0x1d/0x52 [snd_usb_audio] This comes from snd_usb_autoresume() invoking down_read() and it's used in a nested way. Although it's basically safe, per se (as these are read locks), it's better to reduce such spurious warnings. The read lock is needed to guarantee the execution of "shutdown" (cleanup at disconnection) task after all concurrent tasks are finished. This can be implemented in another better way. Also, the current check of chip->in_pm isn't good enough for protecting the racy execution of multiple auto-resumes. This patch rewrites the logic of snd_usb_autoresume() & co; namely, - The recursive call of autopm is avoided by the new refcount, chip->active. The chip->in_pm flag is removed accordingly. - Instead of rwsem, another refcount, chip->usage_count, is introduced for tracking the period to delay the shutdown procedure. At the last clear of this refcount, wake_up() to the shutdown waiter is called. - The shutdown flag is replaced with shutdown atomic count; this is for reducing the lock. - Two new helpers are introduced to simplify the management of these refcounts; snd_usb_lock_shutdown() increases the usage_count, checks the shutdown state, and does autoresume. snd_usb_unlock_shutdown() does the opposite. Most of mixer and other codes just need this, and simply returns an error if it receives an error from lock. Fixes: 9003ebb13f61 ('ALSA: usb-audio: Fix runtime PM unbalance') Reported-and-tested-by: Alexnader Kuleshov <kuleshovmail@gmail.com> Signed-off-by: Takashi Iwai <tiwai@suse.de>
2015-08-25 14:09:00 +00:00
atomic_inc(&chip->usage_count);
if (atomic_read(&chip->shutdown)) {
err = -EIO;
goto error;
}
err = snd_usb_autoresume(chip);
if (err < 0)
goto error;
return 0;
ALSA: usb-audio: Avoid nested autoresume calls After the recent fix of runtime PM for USB-audio driver, we got a lockdep warning like: ============================================= [ INFO: possible recursive locking detected ] 4.2.0-rc8+ #61 Not tainted --------------------------------------------- pulseaudio/980 is trying to acquire lock: (&chip->shutdown_rwsem){.+.+.+}, at: [<ffffffffa0355dac>] snd_usb_autoresume+0x1d/0x52 [snd_usb_audio] but task is already holding lock: (&chip->shutdown_rwsem){.+.+.+}, at: [<ffffffffa0355dac>] snd_usb_autoresume+0x1d/0x52 [snd_usb_audio] This comes from snd_usb_autoresume() invoking down_read() and it's used in a nested way. Although it's basically safe, per se (as these are read locks), it's better to reduce such spurious warnings. The read lock is needed to guarantee the execution of "shutdown" (cleanup at disconnection) task after all concurrent tasks are finished. This can be implemented in another better way. Also, the current check of chip->in_pm isn't good enough for protecting the racy execution of multiple auto-resumes. This patch rewrites the logic of snd_usb_autoresume() & co; namely, - The recursive call of autopm is avoided by the new refcount, chip->active. The chip->in_pm flag is removed accordingly. - Instead of rwsem, another refcount, chip->usage_count, is introduced for tracking the period to delay the shutdown procedure. At the last clear of this refcount, wake_up() to the shutdown waiter is called. - The shutdown flag is replaced with shutdown atomic count; this is for reducing the lock. - Two new helpers are introduced to simplify the management of these refcounts; snd_usb_lock_shutdown() increases the usage_count, checks the shutdown state, and does autoresume. snd_usb_unlock_shutdown() does the opposite. Most of mixer and other codes just need this, and simply returns an error if it receives an error from lock. Fixes: 9003ebb13f61 ('ALSA: usb-audio: Fix runtime PM unbalance') Reported-and-tested-by: Alexnader Kuleshov <kuleshovmail@gmail.com> Signed-off-by: Takashi Iwai <tiwai@suse.de>
2015-08-25 14:09:00 +00:00
error:
if (atomic_dec_and_test(&chip->usage_count))
wake_up(&chip->shutdown_wait);
return err;
}
ALSA: usb-audio: Avoid nested autoresume calls After the recent fix of runtime PM for USB-audio driver, we got a lockdep warning like: ============================================= [ INFO: possible recursive locking detected ] 4.2.0-rc8+ #61 Not tainted --------------------------------------------- pulseaudio/980 is trying to acquire lock: (&chip->shutdown_rwsem){.+.+.+}, at: [<ffffffffa0355dac>] snd_usb_autoresume+0x1d/0x52 [snd_usb_audio] but task is already holding lock: (&chip->shutdown_rwsem){.+.+.+}, at: [<ffffffffa0355dac>] snd_usb_autoresume+0x1d/0x52 [snd_usb_audio] This comes from snd_usb_autoresume() invoking down_read() and it's used in a nested way. Although it's basically safe, per se (as these are read locks), it's better to reduce such spurious warnings. The read lock is needed to guarantee the execution of "shutdown" (cleanup at disconnection) task after all concurrent tasks are finished. This can be implemented in another better way. Also, the current check of chip->in_pm isn't good enough for protecting the racy execution of multiple auto-resumes. This patch rewrites the logic of snd_usb_autoresume() & co; namely, - The recursive call of autopm is avoided by the new refcount, chip->active. The chip->in_pm flag is removed accordingly. - Instead of rwsem, another refcount, chip->usage_count, is introduced for tracking the period to delay the shutdown procedure. At the last clear of this refcount, wake_up() to the shutdown waiter is called. - The shutdown flag is replaced with shutdown atomic count; this is for reducing the lock. - Two new helpers are introduced to simplify the management of these refcounts; snd_usb_lock_shutdown() increases the usage_count, checks the shutdown state, and does autoresume. snd_usb_unlock_shutdown() does the opposite. Most of mixer and other codes just need this, and simply returns an error if it receives an error from lock. Fixes: 9003ebb13f61 ('ALSA: usb-audio: Fix runtime PM unbalance') Reported-and-tested-by: Alexnader Kuleshov <kuleshovmail@gmail.com> Signed-off-by: Takashi Iwai <tiwai@suse.de>
2015-08-25 14:09:00 +00:00
/* autosuspend and unlock the shutdown */
void snd_usb_unlock_shutdown(struct snd_usb_audio *chip)
{
snd_usb_autosuspend(chip);
if (atomic_dec_and_test(&chip->usage_count))
wake_up(&chip->shutdown_wait);
}
#ifdef CONFIG_PM
int snd_usb_autoresume(struct snd_usb_audio *chip)
{
if (atomic_read(&chip->shutdown))
return -EIO;
if (atomic_inc_return(&chip->active) == 1)
return usb_autopm_get_interface(chip->pm_intf);
return 0;
}
void snd_usb_autosuspend(struct snd_usb_audio *chip)
{
ALSA: usb-audio: Avoid nested autoresume calls After the recent fix of runtime PM for USB-audio driver, we got a lockdep warning like: ============================================= [ INFO: possible recursive locking detected ] 4.2.0-rc8+ #61 Not tainted --------------------------------------------- pulseaudio/980 is trying to acquire lock: (&chip->shutdown_rwsem){.+.+.+}, at: [<ffffffffa0355dac>] snd_usb_autoresume+0x1d/0x52 [snd_usb_audio] but task is already holding lock: (&chip->shutdown_rwsem){.+.+.+}, at: [<ffffffffa0355dac>] snd_usb_autoresume+0x1d/0x52 [snd_usb_audio] This comes from snd_usb_autoresume() invoking down_read() and it's used in a nested way. Although it's basically safe, per se (as these are read locks), it's better to reduce such spurious warnings. The read lock is needed to guarantee the execution of "shutdown" (cleanup at disconnection) task after all concurrent tasks are finished. This can be implemented in another better way. Also, the current check of chip->in_pm isn't good enough for protecting the racy execution of multiple auto-resumes. This patch rewrites the logic of snd_usb_autoresume() & co; namely, - The recursive call of autopm is avoided by the new refcount, chip->active. The chip->in_pm flag is removed accordingly. - Instead of rwsem, another refcount, chip->usage_count, is introduced for tracking the period to delay the shutdown procedure. At the last clear of this refcount, wake_up() to the shutdown waiter is called. - The shutdown flag is replaced with shutdown atomic count; this is for reducing the lock. - Two new helpers are introduced to simplify the management of these refcounts; snd_usb_lock_shutdown() increases the usage_count, checks the shutdown state, and does autoresume. snd_usb_unlock_shutdown() does the opposite. Most of mixer and other codes just need this, and simply returns an error if it receives an error from lock. Fixes: 9003ebb13f61 ('ALSA: usb-audio: Fix runtime PM unbalance') Reported-and-tested-by: Alexnader Kuleshov <kuleshovmail@gmail.com> Signed-off-by: Takashi Iwai <tiwai@suse.de>
2015-08-25 14:09:00 +00:00
if (atomic_dec_and_test(&chip->active))
usb_autopm_put_interface(chip->pm_intf);
}
static int usb_audio_suspend(struct usb_interface *intf, pm_message_t message)
{
struct snd_usb_audio *chip = usb_get_intfdata(intf);
struct snd_usb_stream *as;
struct usb_mixer_interface *mixer;
struct list_head *p;
if (chip == (void *)-1L)
return 0;
chip->autosuspended = !!PMSG_IS_AUTO(message);
if (!chip->autosuspended)
snd_power_change_state(chip->card, SNDRV_CTL_POWER_D3hot);
if (!chip->num_suspended_intf++) {
list_for_each_entry(as, &chip->pcm_list, list) {
snd_pcm_suspend_all(as->pcm);
as->substream[0].need_setup_ep =
as->substream[1].need_setup_ep = true;
}
list_for_each(p, &chip->midi_list)
snd_usbmidi_suspend(p);
list_for_each_entry(mixer, &chip->mixer_list, list)
snd_usb_mixer_suspend(mixer);
}
return 0;
}
static int __usb_audio_resume(struct usb_interface *intf, bool reset_resume)
{
struct snd_usb_audio *chip = usb_get_intfdata(intf);
struct usb_mixer_interface *mixer;
struct list_head *p;
int err = 0;
if (chip == (void *)-1L)
return 0;
if (--chip->num_suspended_intf)
return 0;
ALSA: usb-audio: Avoid nested autoresume calls After the recent fix of runtime PM for USB-audio driver, we got a lockdep warning like: ============================================= [ INFO: possible recursive locking detected ] 4.2.0-rc8+ #61 Not tainted --------------------------------------------- pulseaudio/980 is trying to acquire lock: (&chip->shutdown_rwsem){.+.+.+}, at: [<ffffffffa0355dac>] snd_usb_autoresume+0x1d/0x52 [snd_usb_audio] but task is already holding lock: (&chip->shutdown_rwsem){.+.+.+}, at: [<ffffffffa0355dac>] snd_usb_autoresume+0x1d/0x52 [snd_usb_audio] This comes from snd_usb_autoresume() invoking down_read() and it's used in a nested way. Although it's basically safe, per se (as these are read locks), it's better to reduce such spurious warnings. The read lock is needed to guarantee the execution of "shutdown" (cleanup at disconnection) task after all concurrent tasks are finished. This can be implemented in another better way. Also, the current check of chip->in_pm isn't good enough for protecting the racy execution of multiple auto-resumes. This patch rewrites the logic of snd_usb_autoresume() & co; namely, - The recursive call of autopm is avoided by the new refcount, chip->active. The chip->in_pm flag is removed accordingly. - Instead of rwsem, another refcount, chip->usage_count, is introduced for tracking the period to delay the shutdown procedure. At the last clear of this refcount, wake_up() to the shutdown waiter is called. - The shutdown flag is replaced with shutdown atomic count; this is for reducing the lock. - Two new helpers are introduced to simplify the management of these refcounts; snd_usb_lock_shutdown() increases the usage_count, checks the shutdown state, and does autoresume. snd_usb_unlock_shutdown() does the opposite. Most of mixer and other codes just need this, and simply returns an error if it receives an error from lock. Fixes: 9003ebb13f61 ('ALSA: usb-audio: Fix runtime PM unbalance') Reported-and-tested-by: Alexnader Kuleshov <kuleshovmail@gmail.com> Signed-off-by: Takashi Iwai <tiwai@suse.de>
2015-08-25 14:09:00 +00:00
atomic_inc(&chip->active); /* avoid autopm */
/*
* ALSA leaves material resumption to user space
* we just notify and restart the mixers
*/
list_for_each_entry(mixer, &chip->mixer_list, list) {
err = snd_usb_mixer_resume(mixer, reset_resume);
if (err < 0)
goto err_out;
}
list_for_each(p, &chip->midi_list) {
snd_usbmidi_resume(p);
}
if (!chip->autosuspended)
snd_power_change_state(chip->card, SNDRV_CTL_POWER_D0);
chip->autosuspended = 0;
err_out:
ALSA: usb-audio: Avoid nested autoresume calls After the recent fix of runtime PM for USB-audio driver, we got a lockdep warning like: ============================================= [ INFO: possible recursive locking detected ] 4.2.0-rc8+ #61 Not tainted --------------------------------------------- pulseaudio/980 is trying to acquire lock: (&chip->shutdown_rwsem){.+.+.+}, at: [<ffffffffa0355dac>] snd_usb_autoresume+0x1d/0x52 [snd_usb_audio] but task is already holding lock: (&chip->shutdown_rwsem){.+.+.+}, at: [<ffffffffa0355dac>] snd_usb_autoresume+0x1d/0x52 [snd_usb_audio] This comes from snd_usb_autoresume() invoking down_read() and it's used in a nested way. Although it's basically safe, per se (as these are read locks), it's better to reduce such spurious warnings. The read lock is needed to guarantee the execution of "shutdown" (cleanup at disconnection) task after all concurrent tasks are finished. This can be implemented in another better way. Also, the current check of chip->in_pm isn't good enough for protecting the racy execution of multiple auto-resumes. This patch rewrites the logic of snd_usb_autoresume() & co; namely, - The recursive call of autopm is avoided by the new refcount, chip->active. The chip->in_pm flag is removed accordingly. - Instead of rwsem, another refcount, chip->usage_count, is introduced for tracking the period to delay the shutdown procedure. At the last clear of this refcount, wake_up() to the shutdown waiter is called. - The shutdown flag is replaced with shutdown atomic count; this is for reducing the lock. - Two new helpers are introduced to simplify the management of these refcounts; snd_usb_lock_shutdown() increases the usage_count, checks the shutdown state, and does autoresume. snd_usb_unlock_shutdown() does the opposite. Most of mixer and other codes just need this, and simply returns an error if it receives an error from lock. Fixes: 9003ebb13f61 ('ALSA: usb-audio: Fix runtime PM unbalance') Reported-and-tested-by: Alexnader Kuleshov <kuleshovmail@gmail.com> Signed-off-by: Takashi Iwai <tiwai@suse.de>
2015-08-25 14:09:00 +00:00
atomic_dec(&chip->active); /* allow autopm after this point */
return err;
}
static int usb_audio_resume(struct usb_interface *intf)
{
return __usb_audio_resume(intf, false);
}
static int usb_audio_reset_resume(struct usb_interface *intf)
{
return __usb_audio_resume(intf, true);
}
#else
#define usb_audio_suspend NULL
#define usb_audio_resume NULL
#define usb_audio_reset_resume NULL
#endif /* CONFIG_PM */
static struct usb_device_id usb_audio_ids [] = {
#include "quirks-table.h"
{ .match_flags = (USB_DEVICE_ID_MATCH_INT_CLASS | USB_DEVICE_ID_MATCH_INT_SUBCLASS),
.bInterfaceClass = USB_CLASS_AUDIO,
.bInterfaceSubClass = USB_SUBCLASS_AUDIOCONTROL },
{ } /* Terminating entry */
};
MODULE_DEVICE_TABLE(usb, usb_audio_ids);
/*
* entry point for linux usb interface
*/
static struct usb_driver usb_audio_driver = {
.name = "snd-usb-audio",
.probe = usb_audio_probe,
.disconnect = usb_audio_disconnect,
.suspend = usb_audio_suspend,
.resume = usb_audio_resume,
.reset_resume = usb_audio_reset_resume,
.id_table = usb_audio_ids,
.supports_autosuspend = 1,
};
module_usb_driver(usb_audio_driver);