linux/sound/usb/card.h

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#ifndef __USBAUDIO_CARD_H
#define __USBAUDIO_CARD_H
#define MAX_NR_RATES 1024
ALSA: improve buffer size computations for USB PCM audio This patch changes the way URBs are allocated and their sizes are determined for PCM playback in the snd-usb-audio driver. Currently the driver allocates too few URBs for endpoints that don't use implicit sync, making underruns more likely to occur. This may be a holdover from before I/O delays could be measured accurately; in any case, it is no longer necessary. The patch allocates as many URBs as possible, subject to four limitations: The total number of URBs for the endpoint is not allowed to exceed MAX_URBS (which the patch increases from 8 to 12). The total number of packets per URB is not allowed to exceed MAX_PACKS (or MAX_PACKS_HS for high-speed devices), which is decreased from 20 to 6. The total duration of queued data is not allowed to exceed MAX_QUEUE, which is decreased from 24 ms to 18 ms. The total number of ALSA frames in the output queue is not allowed to exceed the ALSA buffer size. The last requirement is the hardest to implement. Currently the number of URBs needed to fill a buffer cannot be determined in advance, because a buffer contains a fixed number of frames whereas the number of frames in an URB varies to match shifts in the device's clock rate. To solve this problem, the patch changes the logic for deciding how many packets an URB should contain. Rather than using as many as possible without exceeding an ALSA period boundary, now the driver uses only as many packets as needed to transfer a predetermined number of frames. As a result, unless the device's clock has an exceedingly variable rate, the number of URBs making up each period (and hence each buffer) will remain constant. The overall effect of the patch is that playback works better in low-latency settings. The user can still specify values for frames/period and periods/buffer that exceed the capabilities of the hardware, of course. But for values that are within those capabilities, the performance will be improved. For example, testing shows that a high-speed device can handle 32 frames/period and 3 periods/buffer at 48 KHz, whereas the current driver starts to get glitchy at 64 frames/period and 2 periods/buffer. A side effect of these changes is that the "nrpacks" module parameter is no longer used. The patch removes it. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> CC: Clemens Ladisch <clemens@ladisch.de> Tested-by: Daniel Mack <zonque@gmail.com> Tested-by: Eldad Zack <eldad@fogrefinery.com> Signed-off-by: Takashi Iwai <tiwai@suse.de>
2013-09-24 19:51:58 +00:00
#define MAX_PACKS 6 /* per URB */
#define MAX_PACKS_HS (MAX_PACKS * 8) /* in high speed mode */
ALSA: improve buffer size computations for USB PCM audio This patch changes the way URBs are allocated and their sizes are determined for PCM playback in the snd-usb-audio driver. Currently the driver allocates too few URBs for endpoints that don't use implicit sync, making underruns more likely to occur. This may be a holdover from before I/O delays could be measured accurately; in any case, it is no longer necessary. The patch allocates as many URBs as possible, subject to four limitations: The total number of URBs for the endpoint is not allowed to exceed MAX_URBS (which the patch increases from 8 to 12). The total number of packets per URB is not allowed to exceed MAX_PACKS (or MAX_PACKS_HS for high-speed devices), which is decreased from 20 to 6. The total duration of queued data is not allowed to exceed MAX_QUEUE, which is decreased from 24 ms to 18 ms. The total number of ALSA frames in the output queue is not allowed to exceed the ALSA buffer size. The last requirement is the hardest to implement. Currently the number of URBs needed to fill a buffer cannot be determined in advance, because a buffer contains a fixed number of frames whereas the number of frames in an URB varies to match shifts in the device's clock rate. To solve this problem, the patch changes the logic for deciding how many packets an URB should contain. Rather than using as many as possible without exceeding an ALSA period boundary, now the driver uses only as many packets as needed to transfer a predetermined number of frames. As a result, unless the device's clock has an exceedingly variable rate, the number of URBs making up each period (and hence each buffer) will remain constant. The overall effect of the patch is that playback works better in low-latency settings. The user can still specify values for frames/period and periods/buffer that exceed the capabilities of the hardware, of course. But for values that are within those capabilities, the performance will be improved. For example, testing shows that a high-speed device can handle 32 frames/period and 3 periods/buffer at 48 KHz, whereas the current driver starts to get glitchy at 64 frames/period and 2 periods/buffer. A side effect of these changes is that the "nrpacks" module parameter is no longer used. The patch removes it. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> CC: Clemens Ladisch <clemens@ladisch.de> Tested-by: Daniel Mack <zonque@gmail.com> Tested-by: Eldad Zack <eldad@fogrefinery.com> Signed-off-by: Takashi Iwai <tiwai@suse.de>
2013-09-24 19:51:58 +00:00
#define MAX_URBS 12
#define SYNC_URBS 4 /* always four urbs for sync */
ALSA: improve buffer size computations for USB PCM audio This patch changes the way URBs are allocated and their sizes are determined for PCM playback in the snd-usb-audio driver. Currently the driver allocates too few URBs for endpoints that don't use implicit sync, making underruns more likely to occur. This may be a holdover from before I/O delays could be measured accurately; in any case, it is no longer necessary. The patch allocates as many URBs as possible, subject to four limitations: The total number of URBs for the endpoint is not allowed to exceed MAX_URBS (which the patch increases from 8 to 12). The total number of packets per URB is not allowed to exceed MAX_PACKS (or MAX_PACKS_HS for high-speed devices), which is decreased from 20 to 6. The total duration of queued data is not allowed to exceed MAX_QUEUE, which is decreased from 24 ms to 18 ms. The total number of ALSA frames in the output queue is not allowed to exceed the ALSA buffer size. The last requirement is the hardest to implement. Currently the number of URBs needed to fill a buffer cannot be determined in advance, because a buffer contains a fixed number of frames whereas the number of frames in an URB varies to match shifts in the device's clock rate. To solve this problem, the patch changes the logic for deciding how many packets an URB should contain. Rather than using as many as possible without exceeding an ALSA period boundary, now the driver uses only as many packets as needed to transfer a predetermined number of frames. As a result, unless the device's clock has an exceedingly variable rate, the number of URBs making up each period (and hence each buffer) will remain constant. The overall effect of the patch is that playback works better in low-latency settings. The user can still specify values for frames/period and periods/buffer that exceed the capabilities of the hardware, of course. But for values that are within those capabilities, the performance will be improved. For example, testing shows that a high-speed device can handle 32 frames/period and 3 periods/buffer at 48 KHz, whereas the current driver starts to get glitchy at 64 frames/period and 2 periods/buffer. A side effect of these changes is that the "nrpacks" module parameter is no longer used. The patch removes it. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> CC: Clemens Ladisch <clemens@ladisch.de> Tested-by: Daniel Mack <zonque@gmail.com> Tested-by: Eldad Zack <eldad@fogrefinery.com> Signed-off-by: Takashi Iwai <tiwai@suse.de>
2013-09-24 19:51:58 +00:00
#define MAX_QUEUE 18 /* try not to exceed this queue length, in ms */
struct audioformat {
struct list_head list;
u64 formats; /* ALSA format bits */
unsigned int channels; /* # channels */
unsigned int fmt_type; /* USB audio format type (1-3) */
unsigned int frame_size; /* samples per frame for non-audio */
int iface; /* interface number */
unsigned char altsetting; /* corresponding alternate setting */
unsigned char altset_idx; /* array index of altenate setting */
unsigned char attributes; /* corresponding attributes of cs endpoint */
unsigned char endpoint; /* endpoint */
unsigned char ep_attr; /* endpoint attributes */
unsigned char datainterval; /* log_2 of data packet interval */
unsigned char protocol; /* UAC_VERSION_1/2 */
unsigned int maxpacksize; /* max. packet size */
unsigned int rates; /* rate bitmasks */
unsigned int rate_min, rate_max; /* min/max rates */
unsigned int nr_rates; /* number of rate table entries */
unsigned int *rate_table; /* rate table */
unsigned char clock; /* associated clock */
struct snd_pcm_chmap_elem *chmap; /* (optional) channel map */
bool dsd_dop; /* add DOP headers in case of DSD samples */
bool dsd_bitrev; /* reverse the bits of each DSD sample */
};
struct snd_usb_substream;
struct snd_usb_endpoint;
struct snd_urb_ctx {
struct urb *urb;
unsigned int buffer_size; /* size of data buffer, if data URB */
struct snd_usb_substream *subs;
struct snd_usb_endpoint *ep;
int index; /* index for urb array */
int packets; /* number of packets per urb */
int packet_size[MAX_PACKS_HS]; /* size of packets for next submission */
struct list_head ready_list;
};
struct snd_usb_endpoint {
struct snd_usb_audio *chip;
int use_count;
int ep_num; /* the referenced endpoint number */
int type; /* SND_USB_ENDPOINT_TYPE_* */
unsigned long flags;
void (*prepare_data_urb) (struct snd_usb_substream *subs,
struct urb *urb);
void (*retire_data_urb) (struct snd_usb_substream *subs,
struct urb *urb);
struct snd_usb_substream *data_subs;
struct snd_usb_endpoint *sync_master;
struct snd_usb_endpoint *sync_slave;
struct snd_urb_ctx urb[MAX_URBS];
struct snd_usb_packet_info {
uint32_t packet_size[MAX_PACKS_HS];
int packets;
} next_packet[MAX_URBS];
int next_packet_read_pos, next_packet_write_pos;
struct list_head ready_playback_urbs;
unsigned int nurbs; /* # urbs */
unsigned long active_mask; /* bitmask of active urbs */
unsigned long unlink_mask; /* bitmask of unlinked urbs */
char *syncbuf; /* sync buffer for all sync URBs */
dma_addr_t sync_dma; /* DMA address of syncbuf */
unsigned int pipe; /* the data i/o pipe */
unsigned int freqn; /* nominal sampling rate in fs/fps in Q16.16 format */
unsigned int freqm; /* momentary sampling rate in fs/fps in Q16.16 format */
int freqshift; /* how much to shift the feedback value to get Q16.16 */
unsigned int freqmax; /* maximum sampling rate, used for buffer management */
unsigned int phase; /* phase accumulator */
unsigned int maxpacksize; /* max packet size in bytes */
unsigned int maxframesize; /* max packet size in frames */
ALSA: improve buffer size computations for USB PCM audio This patch changes the way URBs are allocated and their sizes are determined for PCM playback in the snd-usb-audio driver. Currently the driver allocates too few URBs for endpoints that don't use implicit sync, making underruns more likely to occur. This may be a holdover from before I/O delays could be measured accurately; in any case, it is no longer necessary. The patch allocates as many URBs as possible, subject to four limitations: The total number of URBs for the endpoint is not allowed to exceed MAX_URBS (which the patch increases from 8 to 12). The total number of packets per URB is not allowed to exceed MAX_PACKS (or MAX_PACKS_HS for high-speed devices), which is decreased from 20 to 6. The total duration of queued data is not allowed to exceed MAX_QUEUE, which is decreased from 24 ms to 18 ms. The total number of ALSA frames in the output queue is not allowed to exceed the ALSA buffer size. The last requirement is the hardest to implement. Currently the number of URBs needed to fill a buffer cannot be determined in advance, because a buffer contains a fixed number of frames whereas the number of frames in an URB varies to match shifts in the device's clock rate. To solve this problem, the patch changes the logic for deciding how many packets an URB should contain. Rather than using as many as possible without exceeding an ALSA period boundary, now the driver uses only as many packets as needed to transfer a predetermined number of frames. As a result, unless the device's clock has an exceedingly variable rate, the number of URBs making up each period (and hence each buffer) will remain constant. The overall effect of the patch is that playback works better in low-latency settings. The user can still specify values for frames/period and periods/buffer that exceed the capabilities of the hardware, of course. But for values that are within those capabilities, the performance will be improved. For example, testing shows that a high-speed device can handle 32 frames/period and 3 periods/buffer at 48 KHz, whereas the current driver starts to get glitchy at 64 frames/period and 2 periods/buffer. A side effect of these changes is that the "nrpacks" module parameter is no longer used. The patch removes it. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> CC: Clemens Ladisch <clemens@ladisch.de> Tested-by: Daniel Mack <zonque@gmail.com> Tested-by: Eldad Zack <eldad@fogrefinery.com> Signed-off-by: Takashi Iwai <tiwai@suse.de>
2013-09-24 19:51:58 +00:00
unsigned int max_urb_frames; /* max URB size in frames */
unsigned int curpacksize; /* current packet size in bytes (for capture) */
unsigned int curframesize; /* current packet size in frames (for capture) */
unsigned int syncmaxsize; /* sync endpoint packet size */
unsigned int fill_max:1; /* fill max packet size always */
unsigned int udh01_fb_quirk:1; /* corrupted feedback data */
unsigned int datainterval; /* log_2 of data packet interval */
unsigned int syncinterval; /* P for adaptive mode, 0 otherwise */
unsigned char silence_value;
unsigned int stride;
int iface, altsetting;
int skip_packets; /* quirks for devices to ignore the first n packets
in a stream */
spinlock_t lock;
struct list_head list;
};
struct snd_usb_substream {
struct snd_usb_stream *stream;
struct usb_device *dev;
struct snd_pcm_substream *pcm_substream;
int direction; /* playback or capture */
int interface; /* current interface */
int endpoint; /* assigned endpoint */
struct audioformat *cur_audiofmt; /* current audioformat pointer (for hw_params callback) */
snd_pcm_format_t pcm_format; /* current audio format (for hw_params callback) */
unsigned int channels; /* current number of channels (for hw_params callback) */
unsigned int channels_max; /* max channels in the all audiofmts */
unsigned int cur_rate; /* current rate (for hw_params callback) */
unsigned int period_bytes; /* current period bytes (for hw_params callback) */
ALSA: improve buffer size computations for USB PCM audio This patch changes the way URBs are allocated and their sizes are determined for PCM playback in the snd-usb-audio driver. Currently the driver allocates too few URBs for endpoints that don't use implicit sync, making underruns more likely to occur. This may be a holdover from before I/O delays could be measured accurately; in any case, it is no longer necessary. The patch allocates as many URBs as possible, subject to four limitations: The total number of URBs for the endpoint is not allowed to exceed MAX_URBS (which the patch increases from 8 to 12). The total number of packets per URB is not allowed to exceed MAX_PACKS (or MAX_PACKS_HS for high-speed devices), which is decreased from 20 to 6. The total duration of queued data is not allowed to exceed MAX_QUEUE, which is decreased from 24 ms to 18 ms. The total number of ALSA frames in the output queue is not allowed to exceed the ALSA buffer size. The last requirement is the hardest to implement. Currently the number of URBs needed to fill a buffer cannot be determined in advance, because a buffer contains a fixed number of frames whereas the number of frames in an URB varies to match shifts in the device's clock rate. To solve this problem, the patch changes the logic for deciding how many packets an URB should contain. Rather than using as many as possible without exceeding an ALSA period boundary, now the driver uses only as many packets as needed to transfer a predetermined number of frames. As a result, unless the device's clock has an exceedingly variable rate, the number of URBs making up each period (and hence each buffer) will remain constant. The overall effect of the patch is that playback works better in low-latency settings. The user can still specify values for frames/period and periods/buffer that exceed the capabilities of the hardware, of course. But for values that are within those capabilities, the performance will be improved. For example, testing shows that a high-speed device can handle 32 frames/period and 3 periods/buffer at 48 KHz, whereas the current driver starts to get glitchy at 64 frames/period and 2 periods/buffer. A side effect of these changes is that the "nrpacks" module parameter is no longer used. The patch removes it. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> CC: Clemens Ladisch <clemens@ladisch.de> Tested-by: Daniel Mack <zonque@gmail.com> Tested-by: Eldad Zack <eldad@fogrefinery.com> Signed-off-by: Takashi Iwai <tiwai@suse.de>
2013-09-24 19:51:58 +00:00
unsigned int period_frames; /* current frames per period */
unsigned int buffer_periods; /* current periods per buffer */
unsigned int altset_idx; /* USB data format: index of alternate setting */
unsigned int txfr_quirk:1; /* allow sub-frame alignment */
unsigned int fmt_type; /* USB audio format type (1-3) */
unsigned int pkt_offset_adj; /* Bytes to drop from beginning of packets (for non-compliant devices) */
unsigned int running: 1; /* running status */
unsigned int hwptr_done; /* processed byte position in the buffer */
unsigned int transfer_done; /* processed frames since last period update */
ALSA: improve buffer size computations for USB PCM audio This patch changes the way URBs are allocated and their sizes are determined for PCM playback in the snd-usb-audio driver. Currently the driver allocates too few URBs for endpoints that don't use implicit sync, making underruns more likely to occur. This may be a holdover from before I/O delays could be measured accurately; in any case, it is no longer necessary. The patch allocates as many URBs as possible, subject to four limitations: The total number of URBs for the endpoint is not allowed to exceed MAX_URBS (which the patch increases from 8 to 12). The total number of packets per URB is not allowed to exceed MAX_PACKS (or MAX_PACKS_HS for high-speed devices), which is decreased from 20 to 6. The total duration of queued data is not allowed to exceed MAX_QUEUE, which is decreased from 24 ms to 18 ms. The total number of ALSA frames in the output queue is not allowed to exceed the ALSA buffer size. The last requirement is the hardest to implement. Currently the number of URBs needed to fill a buffer cannot be determined in advance, because a buffer contains a fixed number of frames whereas the number of frames in an URB varies to match shifts in the device's clock rate. To solve this problem, the patch changes the logic for deciding how many packets an URB should contain. Rather than using as many as possible without exceeding an ALSA period boundary, now the driver uses only as many packets as needed to transfer a predetermined number of frames. As a result, unless the device's clock has an exceedingly variable rate, the number of URBs making up each period (and hence each buffer) will remain constant. The overall effect of the patch is that playback works better in low-latency settings. The user can still specify values for frames/period and periods/buffer that exceed the capabilities of the hardware, of course. But for values that are within those capabilities, the performance will be improved. For example, testing shows that a high-speed device can handle 32 frames/period and 3 periods/buffer at 48 KHz, whereas the current driver starts to get glitchy at 64 frames/period and 2 periods/buffer. A side effect of these changes is that the "nrpacks" module parameter is no longer used. The patch removes it. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> CC: Clemens Ladisch <clemens@ladisch.de> Tested-by: Daniel Mack <zonque@gmail.com> Tested-by: Eldad Zack <eldad@fogrefinery.com> Signed-off-by: Takashi Iwai <tiwai@suse.de>
2013-09-24 19:51:58 +00:00
unsigned int frame_limit; /* limits number of packets in URB */
/* data and sync endpoints for this stream */
unsigned int ep_num; /* the endpoint number */
struct snd_usb_endpoint *data_endpoint;
struct snd_usb_endpoint *sync_endpoint;
unsigned long flags;
bool need_setup_ep; /* (re)configure EP at prepare? */
unsigned int speed; /* USB_SPEED_XXX */
u64 formats; /* format bitmasks (all or'ed) */
unsigned int num_formats; /* number of supported audio formats (list) */
struct list_head fmt_list; /* format list */
struct snd_pcm_hw_constraint_list rate_list; /* limited rates */
spinlock_t lock;
int last_frame_number; /* stored frame number */
int last_delay; /* stored delay */
struct {
int marker;
int channel;
int byte_idx;
} dsd_dop;
};
struct snd_usb_stream {
struct snd_usb_audio *chip;
struct snd_pcm *pcm;
int pcm_index;
unsigned int fmt_type; /* USB audio format type (1-3) */
struct snd_usb_substream substream[2];
struct list_head list;
};
#endif /* __USBAUDIO_CARD_H */