| Message ID | 20180416121417.27452-4-tiwai@suse.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi, On Apr 16 2018 21:14, Takashi Iwai wrote: > Yet another slight code cleanup: there are two places where > calculating the PCM delay, and they can be unified in a single > helper. It reduces the multiple open codes. > > Signed-off-by: Takashi Iwai <tiwai@suse.de> > --- > sound/core/pcm_native.c | 36 +++++++++++++++--------------------- > 1 file changed, 15 insertions(+), 21 deletions(-) > > diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c > index eddb0cd6d1eb..81bbe0b3284b 100644 > --- a/sound/core/pcm_native.c > +++ b/sound/core/pcm_native.c > @@ -857,6 +857,18 @@ static int snd_pcm_sw_params_user(struct snd_pcm_substream *substream, > return err; > } > > +static inline snd_pcm_uframes_t > +snd_pcm_calc_delay(struct snd_pcm_substream *substream) > +{ > + snd_pcm_uframes_t delay; > + > + if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) > + delay = snd_pcm_playback_hw_avail(substream->runtime); > + else > + delay = snd_pcm_capture_avail(substream->runtime); > + return delay + substream->runtime->delay; > +} > + > int snd_pcm_status(struct snd_pcm_substream *substream, > struct snd_pcm_status *status) > { > @@ -909,19 +921,7 @@ int snd_pcm_status(struct snd_pcm_substream *substream, > status->appl_ptr = runtime->control->appl_ptr; > status->hw_ptr = runtime->status->hw_ptr; > status->avail = snd_pcm_avail(substream); > - if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) { > - if (runtime->status->state == SNDRV_PCM_STATE_RUNNING || > - runtime->status->state == SNDRV_PCM_STATE_DRAINING) { > - status->delay = runtime->buffer_size - status->avail; > - status->delay += runtime->delay; > - } else > - status->delay = 0; > - } else { > - if (runtime->status->state == SNDRV_PCM_STATE_RUNNING) > - status->delay = status->avail + runtime->delay; > - else > - status->delay = 0; > - } > + status->delay = snd_pcm_calc_delay(substream); > status->avail_max = runtime->avail_max; > status->overrange = runtime->overrange; > runtime->avail_max = 0; > @@ -2655,19 +2655,13 @@ static int snd_pcm_hwsync(struct snd_pcm_substream *substream) > > static snd_pcm_sframes_t snd_pcm_delay(struct snd_pcm_substream *substream) > { > - struct snd_pcm_runtime *runtime = substream->runtime; > int err; > snd_pcm_sframes_t n = 0; > > snd_pcm_stream_lock_irq(substream); > err = do_pcm_hwsync(substream); > - if (!err) { > - if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) > - n = snd_pcm_playback_hw_avail(runtime); > - else > - n = snd_pcm_capture_avail(runtime); > - n += runtime->delay; > - } > + if (!err) > + n = snd_pcm_calc_delay(substream); > snd_pcm_stream_unlock_irq(substream); > return err < 0 ? err : n; > } When any PCM substream is under running state, this patchset is good. Below is short descriptions of calculation in each case. snd_pcm_status() for playback on running * delay = runtime->buffer_size - status->avail (=snd_pcm_playback_hw_avail()) * delay += runtime->delay snd_pcm_status() for capture on running * delay = status->avail (= snd_pcm_avail() = snd_pcm_capture_avail()) * delay += runtime->delay snd_pcm_delay() for playback * delay = snd_pcm_playback_hw_avail() * delay += rutime_delay snd_pcm_delay() for capture * delay = snd_pcm_capture_avail(runtime) * delay += runtime->delay However, under non-running states, I have some suspicion, because originally 'snd_pcm_status()' take 0 in the states while your code manage to calculate it. (sound/core/pcm_native.c) 911 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) { 912 status->avail = snd_pcm_playback_avail(runtime); 913 if (runtime->status->state == SNDRV_PCM_STATE_RUNNING || 914 runtime->status->state == SNDRV_PCM_STATE_DRAINING) { ... 917 } else 918 status->delay = 0; 919 } else { 920 status->avail = snd_pcm_capture_avail(runtime); 921 if (runtime->status->state == SNDRV_PCM_STATE_RUNNING) ... 923 else 924 status->delay = 0; 925 } I think this patch is based on an assumption that hw_ptr is zeroed after stopping PCM substream. On the other hand, I cannot find codes which reset hw_ptr to zero during lifetime of PCM runtime. Any calculation of delay with hw_ptr could return non-zero value in non-running states. This patch can change behaviour of PCM core in a view of userspace applications, in my understanding. Regards Takashi Sakamoto
diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c index eddb0cd6d1eb..81bbe0b3284b 100644 --- a/sound/core/pcm_native.c +++ b/sound/core/pcm_native.c @@ -857,6 +857,18 @@ static int snd_pcm_sw_params_user(struct snd_pcm_substream *substream, return err; } +static inline snd_pcm_uframes_t +snd_pcm_calc_delay(struct snd_pcm_substream *substream) +{ + snd_pcm_uframes_t delay; + + if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) + delay = snd_pcm_playback_hw_avail(substream->runtime); + else + delay = snd_pcm_capture_avail(substream->runtime); + return delay + substream->runtime->delay; +} + int snd_pcm_status(struct snd_pcm_substream *substream, struct snd_pcm_status *status) { @@ -909,19 +921,7 @@ int snd_pcm_status(struct snd_pcm_substream *substream, status->appl_ptr = runtime->control->appl_ptr; status->hw_ptr = runtime->status->hw_ptr; status->avail = snd_pcm_avail(substream); - if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) { - if (runtime->status->state == SNDRV_PCM_STATE_RUNNING || - runtime->status->state == SNDRV_PCM_STATE_DRAINING) { - status->delay = runtime->buffer_size - status->avail; - status->delay += runtime->delay; - } else - status->delay = 0; - } else { - if (runtime->status->state == SNDRV_PCM_STATE_RUNNING) - status->delay = status->avail + runtime->delay; - else - status->delay = 0; - } + status->delay = snd_pcm_calc_delay(substream); status->avail_max = runtime->avail_max; status->overrange = runtime->overrange; runtime->avail_max = 0; @@ -2655,19 +2655,13 @@ static int snd_pcm_hwsync(struct snd_pcm_substream *substream) static snd_pcm_sframes_t snd_pcm_delay(struct snd_pcm_substream *substream) { - struct snd_pcm_runtime *runtime = substream->runtime; int err; snd_pcm_sframes_t n = 0; snd_pcm_stream_lock_irq(substream); err = do_pcm_hwsync(substream); - if (!err) { - if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) - n = snd_pcm_playback_hw_avail(runtime); - else - n = snd_pcm_capture_avail(runtime); - n += runtime->delay; - } + if (!err) + n = snd_pcm_calc_delay(substream); snd_pcm_stream_unlock_irq(substream); return err < 0 ? err : n; }
Yet another slight code cleanup: there are two places where calculating the PCM delay, and they can be unified in a single helper. It reduces the multiple open codes. Signed-off-by: Takashi Iwai <tiwai@suse.de> --- sound/core/pcm_native.c | 36 +++++++++++++++--------------------- 1 file changed, 15 insertions(+), 21 deletions(-)