diff options
Diffstat (limited to 'drivers/staging/vc04_services/bcm2835-audio/bcm2835-pcm.c')
| -rw-r--r-- | drivers/staging/vc04_services/bcm2835-audio/bcm2835-pcm.c | 30 |
1 files changed, 22 insertions, 8 deletions
diff --git a/drivers/staging/vc04_services/bcm2835-audio/bcm2835-pcm.c b/drivers/staging/vc04_services/bcm2835-audio/bcm2835-pcm.c index e66da11af5cf..bc1eaa3a0773 100644 --- a/drivers/staging/vc04_services/bcm2835-audio/bcm2835-pcm.c +++ b/drivers/staging/vc04_services/bcm2835-audio/bcm2835-pcm.c @@ -74,6 +74,7 @@ void bcm2835_playback_fifo(struct bcm2835_alsa_stream *alsa_stream, atomic_set(&alsa_stream->pos, pos); alsa_stream->period_offset += bytes; + alsa_stream->interpolate_start = ktime_get(); if (alsa_stream->period_offset >= alsa_stream->period_size) { alsa_stream->period_offset %= alsa_stream->period_size; snd_pcm_period_elapsed(substream); @@ -164,14 +165,11 @@ static int snd_bcm2835_playback_spdif_open(struct snd_pcm_substream *substream) return snd_bcm2835_playback_open_generic(substream, 1); } -/* close callback */ static int snd_bcm2835_playback_close(struct snd_pcm_substream *substream) { - /* the hardware-specific codes will be here */ - - struct bcm2835_chip *chip; - struct snd_pcm_runtime *runtime; struct bcm2835_alsa_stream *alsa_stream; + struct snd_pcm_runtime *runtime; + struct bcm2835_chip *chip; chip = snd_pcm_substream_chip(substream); mutex_lock(&chip->audio_mutex); @@ -195,20 +193,17 @@ static int snd_bcm2835_playback_close(struct snd_pcm_substream *substream) return 0; } -/* hw_params callback */ static int snd_bcm2835_pcm_hw_params(struct snd_pcm_substream *substream, struct snd_pcm_hw_params *params) { return snd_pcm_lib_malloc_pages(substream, params_buffer_bytes(params)); } -/* hw_free callback */ static int snd_bcm2835_pcm_hw_free(struct snd_pcm_substream *substream) { return snd_pcm_lib_free_pages(substream); } -/* prepare callback */ static int snd_bcm2835_pcm_prepare(struct snd_pcm_substream *substream) { struct bcm2835_chip *chip = snd_pcm_substream_chip(substream); @@ -243,6 +238,7 @@ static int snd_bcm2835_pcm_prepare(struct snd_pcm_substream *substream) atomic_set(&alsa_stream->pos, 0); alsa_stream->period_offset = 0; alsa_stream->draining = false; + alsa_stream->interpolate_start = ktime_get(); return 0; } @@ -292,6 +288,24 @@ snd_bcm2835_pcm_pointer(struct snd_pcm_substream *substream) { struct snd_pcm_runtime *runtime = substream->runtime; struct bcm2835_alsa_stream *alsa_stream = runtime->private_data; + ktime_t now = ktime_get(); + + /* Give userspace better delay reporting by interpolating between GPU + * notifications, assuming audio speed is close enough to the clock + * used for ktime + */ + + if ((ktime_to_ns(alsa_stream->interpolate_start)) && + (ktime_compare(alsa_stream->interpolate_start, now) < 0)) { + u64 interval = + (ktime_to_ns(ktime_sub(now, + alsa_stream->interpolate_start))); + u64 frames_output_in_interval = + div_u64((interval * runtime->rate), 1000000000); + snd_pcm_sframes_t frames_output_in_interval_sized = + -frames_output_in_interval; + runtime->delay = frames_output_in_interval_sized; + } return snd_pcm_indirect_playback_pointer(substream, &alsa_stream->pcm_indirect, |