linux/drivers/gpu/drm/drm_probe_helper.c
Daniel Vetter 8c4ccc4ab6 drm/probe-helper: Grab mode_config.mutex in poll_init/enable
So on first looks this seems superflous since drivers should ensure
correct ordering to not make this a problem. Otoh ordering constraints
between hdp, fbdev load and enabling polling are already tricky on
some hardware and it helps to be more robust.

But the real goal is to just shut up a locking WARN_ON I'd like to
add, which means init code gets some additional locks just for
uniformity.

v2: Also grab the lock for the public poll_enable, not just poll_init
which is used for resume, with the same justification.

Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
2015-07-22 16:25:45 +02:00

533 lines
17 KiB
C

/*
* Copyright (c) 2006-2008 Intel Corporation
* Copyright (c) 2007 Dave Airlie <airlied@linux.ie>
*
* DRM core CRTC related functions
*
* Permission to use, copy, modify, distribute, and sell this software and its
* documentation for any purpose is hereby granted without fee, provided that
* the above copyright notice appear in all copies and that both that copyright
* notice and this permission notice appear in supporting documentation, and
* that the name of the copyright holders not be used in advertising or
* publicity pertaining to distribution of the software without specific,
* written prior permission. The copyright holders make no representations
* about the suitability of this software for any purpose. It is provided "as
* is" without express or implied warranty.
*
* THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
* INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
* EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
* CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
* DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
* TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
* OF THIS SOFTWARE.
*
* Authors:
* Keith Packard
* Eric Anholt <eric@anholt.net>
* Dave Airlie <airlied@linux.ie>
* Jesse Barnes <jesse.barnes@intel.com>
*/
#include <linux/export.h>
#include <linux/moduleparam.h>
#include <drm/drmP.h>
#include <drm/drm_crtc.h>
#include <drm/drm_fourcc.h>
#include <drm/drm_crtc_helper.h>
#include <drm/drm_fb_helper.h>
#include <drm/drm_edid.h>
/**
* DOC: output probing helper overview
*
* This library provides some helper code for output probing. It provides an
* implementation of the core connector->fill_modes interface with
* drm_helper_probe_single_connector_modes.
*
* It also provides support for polling connectors with a work item and for
* generic hotplug interrupt handling where the driver doesn't or cannot keep
* track of a per-connector hpd interrupt.
*
* This helper library can be used independently of the modeset helper library.
* Drivers can also overwrite different parts e.g. use their own hotplug
* handling code to avoid probing unrelated outputs.
*/
static bool drm_kms_helper_poll = true;
module_param_named(poll, drm_kms_helper_poll, bool, 0600);
static enum drm_mode_status
drm_mode_validate_flag(const struct drm_display_mode *mode,
int flags)
{
if ((mode->flags & DRM_MODE_FLAG_INTERLACE) &&
!(flags & DRM_MODE_FLAG_INTERLACE))
return MODE_NO_INTERLACE;
if ((mode->flags & DRM_MODE_FLAG_DBLSCAN) &&
!(flags & DRM_MODE_FLAG_DBLSCAN))
return MODE_NO_DBLESCAN;
if ((mode->flags & DRM_MODE_FLAG_3D_MASK) &&
!(flags & DRM_MODE_FLAG_3D_MASK))
return MODE_NO_STEREO;
return MODE_OK;
}
static int drm_helper_probe_add_cmdline_mode(struct drm_connector *connector)
{
struct drm_display_mode *mode;
if (!connector->cmdline_mode.specified)
return 0;
mode = drm_mode_create_from_cmdline_mode(connector->dev,
&connector->cmdline_mode);
if (mode == NULL)
return 0;
drm_mode_probed_add(connector, mode);
return 1;
}
#define DRM_OUTPUT_POLL_PERIOD (10*HZ)
static void __drm_kms_helper_poll_enable(struct drm_device *dev)
{
bool poll = false;
struct drm_connector *connector;
WARN_ON(!mutex_is_locked(&dev->mode_config.mutex));
if (!dev->mode_config.poll_enabled || !drm_kms_helper_poll)
return;
drm_for_each_connector(connector, dev) {
if (connector->polled & (DRM_CONNECTOR_POLL_CONNECT |
DRM_CONNECTOR_POLL_DISCONNECT))
poll = true;
}
if (poll)
schedule_delayed_work(&dev->mode_config.output_poll_work, DRM_OUTPUT_POLL_PERIOD);
}
static int drm_helper_probe_single_connector_modes_merge_bits(struct drm_connector *connector,
uint32_t maxX, uint32_t maxY, bool merge_type_bits)
{
struct drm_device *dev = connector->dev;
struct drm_display_mode *mode;
const struct drm_connector_helper_funcs *connector_funcs =
connector->helper_private;
int count = 0;
int mode_flags = 0;
bool verbose_prune = true;
enum drm_connector_status old_status;
WARN_ON(!mutex_is_locked(&dev->mode_config.mutex));
DRM_DEBUG_KMS("[CONNECTOR:%d:%s]\n", connector->base.id,
connector->name);
/* set all modes to the unverified state */
list_for_each_entry(mode, &connector->modes, head)
mode->status = MODE_UNVERIFIED;
if (connector->force) {
if (connector->force == DRM_FORCE_ON ||
connector->force == DRM_FORCE_ON_DIGITAL)
connector->status = connector_status_connected;
else
connector->status = connector_status_disconnected;
if (connector->funcs->force)
connector->funcs->force(connector);
} else {
old_status = connector->status;
connector->status = connector->funcs->detect(connector, true);
/*
* Normally either the driver's hpd code or the poll loop should
* pick up any changes and fire the hotplug event. But if
* userspace sneaks in a probe, we might miss a change. Hence
* check here, and if anything changed start the hotplug code.
*/
if (old_status != connector->status) {
DRM_DEBUG_KMS("[CONNECTOR:%d:%s] status updated from %d to %d\n",
connector->base.id,
connector->name,
old_status, connector->status);
/*
* The hotplug event code might call into the fb
* helpers, and so expects that we do not hold any
* locks. Fire up the poll struct instead, it will
* disable itself again.
*/
dev->mode_config.delayed_event = true;
if (dev->mode_config.poll_enabled)
schedule_delayed_work(&dev->mode_config.output_poll_work,
0);
}
}
/* Re-enable polling in case the global poll config changed. */
if (drm_kms_helper_poll != dev->mode_config.poll_running)
__drm_kms_helper_poll_enable(dev);
dev->mode_config.poll_running = drm_kms_helper_poll;
if (connector->status == connector_status_disconnected) {
DRM_DEBUG_KMS("[CONNECTOR:%d:%s] disconnected\n",
connector->base.id, connector->name);
drm_mode_connector_update_edid_property(connector, NULL);
verbose_prune = false;
goto prune;
}
#ifdef CONFIG_DRM_LOAD_EDID_FIRMWARE
count = drm_load_edid_firmware(connector);
if (count == 0)
#endif
{
if (connector->override_edid) {
struct edid *edid = (struct edid *) connector->edid_blob_ptr->data;
count = drm_add_edid_modes(connector, edid);
drm_edid_to_eld(connector, edid);
} else
count = (*connector_funcs->get_modes)(connector);
}
if (count == 0 && connector->status == connector_status_connected)
count = drm_add_modes_noedid(connector, 1024, 768);
count += drm_helper_probe_add_cmdline_mode(connector);
if (count == 0)
goto prune;
drm_mode_connector_list_update(connector, merge_type_bits);
if (connector->interlace_allowed)
mode_flags |= DRM_MODE_FLAG_INTERLACE;
if (connector->doublescan_allowed)
mode_flags |= DRM_MODE_FLAG_DBLSCAN;
if (connector->stereo_allowed)
mode_flags |= DRM_MODE_FLAG_3D_MASK;
list_for_each_entry(mode, &connector->modes, head) {
mode->status = drm_mode_validate_basic(mode);
if (mode->status == MODE_OK)
mode->status = drm_mode_validate_size(mode, maxX, maxY);
if (mode->status == MODE_OK)
mode->status = drm_mode_validate_flag(mode, mode_flags);
if (mode->status == MODE_OK && connector_funcs->mode_valid)
mode->status = connector_funcs->mode_valid(connector,
mode);
}
prune:
drm_mode_prune_invalid(dev, &connector->modes, verbose_prune);
if (list_empty(&connector->modes))
return 0;
list_for_each_entry(mode, &connector->modes, head)
mode->vrefresh = drm_mode_vrefresh(mode);
drm_mode_sort(&connector->modes);
DRM_DEBUG_KMS("[CONNECTOR:%d:%s] probed modes :\n", connector->base.id,
connector->name);
list_for_each_entry(mode, &connector->modes, head) {
drm_mode_set_crtcinfo(mode, CRTC_INTERLACE_HALVE_V);
drm_mode_debug_printmodeline(mode);
}
return count;
}
/**
* drm_helper_probe_single_connector_modes - get complete set of display modes
* @connector: connector to probe
* @maxX: max width for modes
* @maxY: max height for modes
*
* Based on the helper callbacks implemented by @connector try to detect all
* valid modes. Modes will first be added to the connector's probed_modes list,
* then culled (based on validity and the @maxX, @maxY parameters) and put into
* the normal modes list.
*
* Intended to be use as a generic implementation of the ->fill_modes()
* @connector vfunc for drivers that use the crtc helpers for output mode
* filtering and detection.
*
* Returns:
* The number of modes found on @connector.
*/
int drm_helper_probe_single_connector_modes(struct drm_connector *connector,
uint32_t maxX, uint32_t maxY)
{
return drm_helper_probe_single_connector_modes_merge_bits(connector, maxX, maxY, true);
}
EXPORT_SYMBOL(drm_helper_probe_single_connector_modes);
/**
* drm_helper_probe_single_connector_modes_nomerge - get complete set of display modes
* @connector: connector to probe
* @maxX: max width for modes
* @maxY: max height for modes
*
* This operates like drm_hehlper_probe_single_connector_modes except it
* replaces the mode bits instead of merging them for preferred modes.
*/
int drm_helper_probe_single_connector_modes_nomerge(struct drm_connector *connector,
uint32_t maxX, uint32_t maxY)
{
return drm_helper_probe_single_connector_modes_merge_bits(connector, maxX, maxY, false);
}
EXPORT_SYMBOL(drm_helper_probe_single_connector_modes_nomerge);
/**
* drm_kms_helper_hotplug_event - fire off KMS hotplug events
* @dev: drm_device whose connector state changed
*
* This function fires off the uevent for userspace and also calls the
* output_poll_changed function, which is most commonly used to inform the fbdev
* emulation code and allow it to update the fbcon output configuration.
*
* Drivers should call this from their hotplug handling code when a change is
* detected. Note that this function does not do any output detection of its
* own, like drm_helper_hpd_irq_event() does - this is assumed to be done by the
* driver already.
*
* This function must be called from process context with no mode
* setting locks held.
*/
void drm_kms_helper_hotplug_event(struct drm_device *dev)
{
/* send a uevent + call fbdev */
drm_sysfs_hotplug_event(dev);
if (dev->mode_config.funcs->output_poll_changed)
dev->mode_config.funcs->output_poll_changed(dev);
}
EXPORT_SYMBOL(drm_kms_helper_hotplug_event);
static void output_poll_execute(struct work_struct *work)
{
struct delayed_work *delayed_work = to_delayed_work(work);
struct drm_device *dev = container_of(delayed_work, struct drm_device, mode_config.output_poll_work);
struct drm_connector *connector;
enum drm_connector_status old_status;
bool repoll = false, changed;
/* Pick up any changes detected by the probe functions. */
changed = dev->mode_config.delayed_event;
dev->mode_config.delayed_event = false;
if (!drm_kms_helper_poll)
goto out;
mutex_lock(&dev->mode_config.mutex);
drm_for_each_connector(connector, dev) {
/* Ignore forced connectors. */
if (connector->force)
continue;
/* Ignore HPD capable connectors and connectors where we don't
* want any hotplug detection at all for polling. */
if (!connector->polled || connector->polled == DRM_CONNECTOR_POLL_HPD)
continue;
old_status = connector->status;
/* if we are connected and don't want to poll for disconnect
skip it */
if (old_status == connector_status_connected &&
!(connector->polled & DRM_CONNECTOR_POLL_DISCONNECT))
continue;
repoll = true;
connector->status = connector->funcs->detect(connector, false);
if (old_status != connector->status) {
const char *old, *new;
/*
* The poll work sets force=false when calling detect so
* that drivers can avoid to do disruptive tests (e.g.
* when load detect cycles could cause flickering on
* other, running displays). This bears the risk that we
* flip-flop between unknown here in the poll work and
* the real state when userspace forces a full detect
* call after receiving a hotplug event due to this
* change.
*
* Hence clamp an unknown detect status to the old
* value.
*/
if (connector->status == connector_status_unknown) {
connector->status = old_status;
continue;
}
old = drm_get_connector_status_name(old_status);
new = drm_get_connector_status_name(connector->status);
DRM_DEBUG_KMS("[CONNECTOR:%d:%s] "
"status updated from %s to %s\n",
connector->base.id,
connector->name,
old, new);
changed = true;
}
}
mutex_unlock(&dev->mode_config.mutex);
out:
if (changed)
drm_kms_helper_hotplug_event(dev);
if (repoll)
schedule_delayed_work(delayed_work, DRM_OUTPUT_POLL_PERIOD);
}
/**
* drm_kms_helper_poll_disable - disable output polling
* @dev: drm_device
*
* This function disables the output polling work.
*
* Drivers can call this helper from their device suspend implementation. It is
* not an error to call this even when output polling isn't enabled or arlready
* disabled.
*/
void drm_kms_helper_poll_disable(struct drm_device *dev)
{
if (!dev->mode_config.poll_enabled)
return;
cancel_delayed_work_sync(&dev->mode_config.output_poll_work);
}
EXPORT_SYMBOL(drm_kms_helper_poll_disable);
/**
* drm_kms_helper_poll_enable - re-enable output polling.
* @dev: drm_device
*
* This function re-enables the output polling work.
*
* Drivers can call this helper from their device resume implementation. It is
* an error to call this when the output polling support has not yet been set
* up.
*/
void drm_kms_helper_poll_enable(struct drm_device *dev)
{
mutex_lock(&dev->mode_config.mutex);
__drm_kms_helper_poll_enable(dev);
mutex_unlock(&dev->mode_config.mutex);
}
EXPORT_SYMBOL(drm_kms_helper_poll_enable);
/**
* drm_kms_helper_poll_init - initialize and enable output polling
* @dev: drm_device
*
* This function intializes and then also enables output polling support for
* @dev. Drivers which do not have reliable hotplug support in hardware can use
* this helper infrastructure to regularly poll such connectors for changes in
* their connection state.
*
* Drivers can control which connectors are polled by setting the
* DRM_CONNECTOR_POLL_CONNECT and DRM_CONNECTOR_POLL_DISCONNECT flags. On
* connectors where probing live outputs can result in visual distortion drivers
* should not set the DRM_CONNECTOR_POLL_DISCONNECT flag to avoid this.
* Connectors which have no flag or only DRM_CONNECTOR_POLL_HPD set are
* completely ignored by the polling logic.
*
* Note that a connector can be both polled and probed from the hotplug handler,
* in case the hotplug interrupt is known to be unreliable.
*/
void drm_kms_helper_poll_init(struct drm_device *dev)
{
INIT_DELAYED_WORK(&dev->mode_config.output_poll_work, output_poll_execute);
dev->mode_config.poll_enabled = true;
drm_kms_helper_poll_enable(dev);
}
EXPORT_SYMBOL(drm_kms_helper_poll_init);
/**
* drm_kms_helper_poll_fini - disable output polling and clean it up
* @dev: drm_device
*/
void drm_kms_helper_poll_fini(struct drm_device *dev)
{
drm_kms_helper_poll_disable(dev);
}
EXPORT_SYMBOL(drm_kms_helper_poll_fini);
/**
* drm_helper_hpd_irq_event - hotplug processing
* @dev: drm_device
*
* Drivers can use this helper function to run a detect cycle on all connectors
* which have the DRM_CONNECTOR_POLL_HPD flag set in their &polled member. All
* other connectors are ignored, which is useful to avoid reprobing fixed
* panels.
*
* This helper function is useful for drivers which can't or don't track hotplug
* interrupts for each connector.
*
* Drivers which support hotplug interrupts for each connector individually and
* which have a more fine-grained detect logic should bypass this code and
* directly call drm_kms_helper_hotplug_event() in case the connector state
* changed.
*
* This function must be called from process context with no mode
* setting locks held.
*
* Note that a connector can be both polled and probed from the hotplug handler,
* in case the hotplug interrupt is known to be unreliable.
*/
bool drm_helper_hpd_irq_event(struct drm_device *dev)
{
struct drm_connector *connector;
enum drm_connector_status old_status;
bool changed = false;
if (!dev->mode_config.poll_enabled)
return false;
mutex_lock(&dev->mode_config.mutex);
drm_for_each_connector(connector, dev) {
/* Only handle HPD capable connectors. */
if (!(connector->polled & DRM_CONNECTOR_POLL_HPD))
continue;
old_status = connector->status;
connector->status = connector->funcs->detect(connector, false);
DRM_DEBUG_KMS("[CONNECTOR:%d:%s] status updated from %s to %s\n",
connector->base.id,
connector->name,
drm_get_connector_status_name(old_status),
drm_get_connector_status_name(connector->status));
if (old_status != connector->status)
changed = true;
}
mutex_unlock(&dev->mode_config.mutex);
if (changed)
drm_kms_helper_hotplug_event(dev);
return changed;
}
EXPORT_SYMBOL(drm_helper_hpd_irq_event);