From 15c0cee6c809a137e0fc7f1d2b0867cc03473c0c Mon Sep 17 00:00:00 2001 From: Ben Collins Date: Fri, 28 May 2010 11:43:45 -0400 Subject: ALSA: pcm: Define G723 3-bit and 5-bit formats This defines the 24bps and 40bps (8khz sample rate) G.723 codec formats. They are going to be used once I submit the driver for an mpeg4/g723 compression card. I've updated the signed value to -1 as per Takashi's comments since these are non-linear formats. Signed-off-by: Ben Collins Signed-off-by: Takashi Iwai --- include/sound/pcm.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'include/sound/pcm.h') diff --git a/include/sound/pcm.h b/include/sound/pcm.h index dd76cde..07fd630 100644 --- a/include/sound/pcm.h +++ b/include/sound/pcm.h @@ -174,6 +174,10 @@ struct snd_pcm_ops { #define SNDRV_PCM_FMTBIT_U18_3LE (1ULL << SNDRV_PCM_FORMAT_U18_3LE) #define SNDRV_PCM_FMTBIT_S18_3BE (1ULL << SNDRV_PCM_FORMAT_S18_3BE) #define SNDRV_PCM_FMTBIT_U18_3BE (1ULL << SNDRV_PCM_FORMAT_U18_3BE) +#define SNDRV_PCM_FMTBIT_G723_24 (1ULL << SNDRV_PCM_FORMAT_G723_24) +#define SNDRV_PCM_FMTBIT_G723_24_1B (1ULL << SNDRV_PCM_FORMAT_G723_24_1B) +#define SNDRV_PCM_FMTBIT_G723_40 (1ULL << SNDRV_PCM_FORMAT_G723_40) +#define SNDRV_PCM_FMTBIT_G723_40_1B (1ULL << SNDRV_PCM_FORMAT_G723_40_1B) #ifdef SNDRV_LITTLE_ENDIAN #define SNDRV_PCM_FMTBIT_S16 SNDRV_PCM_FMTBIT_S16_LE -- cgit v1.1 From 5daeba34d2aab669aea07abee13d53cd116578fb Mon Sep 17 00:00:00 2001 From: David Dillow Date: Sun, 27 Jun 2010 00:13:20 +0200 Subject: ALSA: pcm_lib: avoid timing jitter in snd_pcm_read/write() When using poll() to wait for the next period -- or avail_min samples -- one gets a consistent delay for each system call that is usually just a little short of the selected period time. However, When using snd_pcm_read/write(), one gets a jittery delay that alternates between less than a millisecond and approximately two period times. This is caused by snd_pcm_lib_{read,write}1() transferring any available samples to the user's buffer and adjusting the application pointer prior to sleeping to the end of the current period. When the next period interrupt occurs, there is then less than avail_min samples remaining to be transferred in the period, so we end up sleeping until a second period occurs. This is solved by using runtime->twake as the number of samples needed for a wakeup in addition to selecting the proper wait queue to wake in snd_pcm_update_state(). This requires twake to be non-zero when used by snd_pcm_lib_{read,write}1() even if avail_min is zero. Signed-off-by: Dave Dillow Signed-off-by: Jaroslav Kysela --- include/sound/pcm.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/sound/pcm.h') diff --git a/include/sound/pcm.h b/include/sound/pcm.h index dd76cde..83c6fa6 100644 --- a/include/sound/pcm.h +++ b/include/sound/pcm.h @@ -313,7 +313,7 @@ struct snd_pcm_runtime { struct snd_pcm_mmap_control *control; /* -- locking / scheduling -- */ - unsigned int twake: 1; /* do transfer (!poll) wakeup */ + snd_pcm_uframes_t twake; /* do transfer (!poll) wakeup if non-zero */ wait_queue_head_t sleep; /* poll sleep */ wait_queue_head_t tsleep; /* transfer sleep */ struct fasync_struct *fasync; -- cgit v1.1