* [PATCHv2 1/1] pcm_pulse: set prebuf parameter according to software parameters
@ 2012-11-18 10:01 Rémi Denis-Courmont
2012-11-19 18:09 ` Takashi Iwai
0 siblings, 1 reply; 4+ messages in thread
From: Rémi Denis-Courmont @ 2012-11-18 10:01 UTC (permalink / raw)
To: alsa-devel; +Cc: Rémi Denis-Courmont
The current default value for prebuf is very high, almost the full
virtual ALSA buffer. This breaks some application especially where
low latency is involved.
This patch makes pcm_pulse implement the sw_params callback and get
the prebuf value from the ALSA software parameters. Thus the
trigger latency is much more like what an ALSA application should
expect from an ALSA PCM device.
---
pulse/pcm_pulse.c | 32 ++++++++++++++++++++++++++++++--
1 file changed, 30 insertions(+), 2 deletions(-)
diff --git a/pulse/pcm_pulse.c b/pulse/pcm_pulse.c
index 24fd4da..4226d30 100644
--- a/pulse/pcm_pulse.c
+++ b/pulse/pcm_pulse.c
@@ -854,8 +854,9 @@ static int pulse_hw_params(snd_pcm_ioplug_t * io,
4 * 1024 * 1024;
pcm->buffer_attr.tlength =
io->buffer_size * pcm->frame_size;
- pcm->buffer_attr.prebuf =
- (io->buffer_size - io->period_size) * pcm->frame_size;
+ if (pcm->buffer_attr.prebuf == (uint32_t)-1)
+ pcm->buffer_attr.prebuf =
+ (io->buffer_size - io->period_size) * pcm->frame_size;
pcm->buffer_attr.minreq = io->period_size * pcm->frame_size;
pcm->buffer_attr.fragsize = io->period_size * pcm->frame_size;
@@ -865,6 +866,31 @@ static int pulse_hw_params(snd_pcm_ioplug_t * io,
return err;
}
+static int pulse_sw_params(snd_pcm_ioplug_t *io, snd_pcm_sw_params_t *params)
+{
+ snd_pcm_pulse_t *pcm = io->private_data;
+ snd_pcm_uframes_t start_threshold;
+
+ assert(pcm);
+
+ if (!pcm->p || !pcm->p->mainloop)
+ return -EBADFD;
+
+ pa_threaded_mainloop_lock(pcm->p->mainloop);
+
+ snd_pcm_sw_params_get_start_threshold(params, &start_threshold);
+
+ /* At least one period to keep PulseAudio happy */
+ if (start_threshold < io->period_size)
+ start_threshold = io->period_size;
+
+ pcm->buffer_attr.prebuf = start_threshold * pcm->frame_size;
+
+ pa_threaded_mainloop_unlock(pcm->p->mainloop);
+
+ return 0;
+}
+
static int pulse_close(snd_pcm_ioplug_t * io)
{
snd_pcm_pulse_t *pcm = io->private_data;
@@ -931,6 +957,7 @@ static const snd_pcm_ioplug_callback_t pulse_playback_callback = {
.poll_revents = pulse_pcm_poll_revents,
.prepare = pulse_prepare,
.hw_params = pulse_hw_params,
+ .sw_params = pulse_sw_params,
.close = pulse_close,
.pause = pulse_pause
};
@@ -1088,6 +1115,7 @@ SND_PCM_PLUGIN_DEFINE_FUNC(pulse)
}
pcm->handle_underrun = handle_underrun;
+ pcm->buffer_attr.prebuf = -1;
err = pulse_connect(pcm->p, server, fallback_name != NULL);
if (err < 0)
--
1.7.10.4
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCHv2 1/1] pcm_pulse: set prebuf parameter according to software parameters
2012-11-18 10:01 [PATCHv2 1/1] pcm_pulse: set prebuf parameter according to software parameters Rémi Denis-Courmont
@ 2012-11-19 18:09 ` Takashi Iwai
2012-11-20 7:51 ` David Henningsson
0 siblings, 1 reply; 4+ messages in thread
From: Takashi Iwai @ 2012-11-19 18:09 UTC (permalink / raw)
To: Rémi Denis-Courmont; +Cc: alsa-devel, David Henningsson
At Sun, 18 Nov 2012 12:01:49 +0200,
Rémi Denis-Courmont wrote:
>
> The current default value for prebuf is very high, almost the full
> virtual ALSA buffer. This breaks some application especially where
> low latency is involved.
>
> This patch makes pcm_pulse implement the sw_params callback and get
> the prebuf value from the ALSA software parameters. Thus the
> trigger latency is much more like what an ALSA application should
> expect from an ALSA PCM device.
Looks good to me. David, could you review?
Also, the first patch isn't needed, right?
Takashi
> ---
> pulse/pcm_pulse.c | 32 ++++++++++++++++++++++++++++++--
> 1 file changed, 30 insertions(+), 2 deletions(-)
>
> diff --git a/pulse/pcm_pulse.c b/pulse/pcm_pulse.c
> index 24fd4da..4226d30 100644
> --- a/pulse/pcm_pulse.c
> +++ b/pulse/pcm_pulse.c
> @@ -854,8 +854,9 @@ static int pulse_hw_params(snd_pcm_ioplug_t * io,
> 4 * 1024 * 1024;
> pcm->buffer_attr.tlength =
> io->buffer_size * pcm->frame_size;
> - pcm->buffer_attr.prebuf =
> - (io->buffer_size - io->period_size) * pcm->frame_size;
> + if (pcm->buffer_attr.prebuf == (uint32_t)-1)
> + pcm->buffer_attr.prebuf =
> + (io->buffer_size - io->period_size) * pcm->frame_size;
> pcm->buffer_attr.minreq = io->period_size * pcm->frame_size;
> pcm->buffer_attr.fragsize = io->period_size * pcm->frame_size;
>
> @@ -865,6 +866,31 @@ static int pulse_hw_params(snd_pcm_ioplug_t * io,
> return err;
> }
>
> +static int pulse_sw_params(snd_pcm_ioplug_t *io, snd_pcm_sw_params_t *params)
> +{
> + snd_pcm_pulse_t *pcm = io->private_data;
> + snd_pcm_uframes_t start_threshold;
> +
> + assert(pcm);
> +
> + if (!pcm->p || !pcm->p->mainloop)
> + return -EBADFD;
> +
> + pa_threaded_mainloop_lock(pcm->p->mainloop);
> +
> + snd_pcm_sw_params_get_start_threshold(params, &start_threshold);
> +
> + /* At least one period to keep PulseAudio happy */
> + if (start_threshold < io->period_size)
> + start_threshold = io->period_size;
> +
> + pcm->buffer_attr.prebuf = start_threshold * pcm->frame_size;
> +
> + pa_threaded_mainloop_unlock(pcm->p->mainloop);
> +
> + return 0;
> +}
> +
> static int pulse_close(snd_pcm_ioplug_t * io)
> {
> snd_pcm_pulse_t *pcm = io->private_data;
> @@ -931,6 +957,7 @@ static const snd_pcm_ioplug_callback_t pulse_playback_callback = {
> .poll_revents = pulse_pcm_poll_revents,
> .prepare = pulse_prepare,
> .hw_params = pulse_hw_params,
> + .sw_params = pulse_sw_params,
> .close = pulse_close,
> .pause = pulse_pause
> };
> @@ -1088,6 +1115,7 @@ SND_PCM_PLUGIN_DEFINE_FUNC(pulse)
> }
>
> pcm->handle_underrun = handle_underrun;
> + pcm->buffer_attr.prebuf = -1;
>
> err = pulse_connect(pcm->p, server, fallback_name != NULL);
> if (err < 0)
> --
> 1.7.10.4
>
> _______________________________________________
> Alsa-devel mailing list
> Alsa-devel@alsa-project.org
> http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
>
_______________________________________________
Alsa-devel mailing list
Alsa-devel@alsa-project.org
http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCHv2 1/1] pcm_pulse: set prebuf parameter according to software parameters
2012-11-19 18:09 ` Takashi Iwai
@ 2012-11-20 7:51 ` David Henningsson
2012-11-20 7:57 ` Takashi Iwai
0 siblings, 1 reply; 4+ messages in thread
From: David Henningsson @ 2012-11-20 7:51 UTC (permalink / raw)
To: Takashi Iwai; +Cc: alsa-devel, Rémi Denis-Courmont
On 11/19/2012 07:09 PM, Takashi Iwai wrote:
> At Sun, 18 Nov 2012 12:01:49 +0200,
> Rémi Denis-Courmont wrote:
>>
>> The current default value for prebuf is very high, almost the full
>> virtual ALSA buffer. This breaks some application especially where
>> low latency is involved.
>>
>> This patch makes pcm_pulse implement the sw_params callback and get
>> the prebuf value from the ALSA software parameters. Thus the
>> trigger latency is much more like what an ALSA application should
>> expect from an ALSA PCM device.
>
> Looks good to me. David, could you review?
I think so too.
Acked-by: David Henningsson <david.henningsson@canonical.com>
> Also, the first patch isn't needed, right?
I think the "pcm_pulse: do not trigger immediately at start" patch
should not be applied.
>
>
> Takashi
>
>> ---
>> pulse/pcm_pulse.c | 32 ++++++++++++++++++++++++++++++--
>> 1 file changed, 30 insertions(+), 2 deletions(-)
>>
>> diff --git a/pulse/pcm_pulse.c b/pulse/pcm_pulse.c
>> index 24fd4da..4226d30 100644
>> --- a/pulse/pcm_pulse.c
>> +++ b/pulse/pcm_pulse.c
>> @@ -854,8 +854,9 @@ static int pulse_hw_params(snd_pcm_ioplug_t * io,
>> 4 * 1024 * 1024;
>> pcm->buffer_attr.tlength =
>> io->buffer_size * pcm->frame_size;
>> - pcm->buffer_attr.prebuf =
>> - (io->buffer_size - io->period_size) * pcm->frame_size;
>> + if (pcm->buffer_attr.prebuf == (uint32_t)-1)
>> + pcm->buffer_attr.prebuf =
>> + (io->buffer_size - io->period_size) * pcm->frame_size;
>> pcm->buffer_attr.minreq = io->period_size * pcm->frame_size;
>> pcm->buffer_attr.fragsize = io->period_size * pcm->frame_size;
>>
>> @@ -865,6 +866,31 @@ static int pulse_hw_params(snd_pcm_ioplug_t * io,
>> return err;
>> }
>>
>> +static int pulse_sw_params(snd_pcm_ioplug_t *io, snd_pcm_sw_params_t *params)
>> +{
>> + snd_pcm_pulse_t *pcm = io->private_data;
>> + snd_pcm_uframes_t start_threshold;
>> +
>> + assert(pcm);
>> +
>> + if (!pcm->p || !pcm->p->mainloop)
>> + return -EBADFD;
>> +
>> + pa_threaded_mainloop_lock(pcm->p->mainloop);
>> +
>> + snd_pcm_sw_params_get_start_threshold(params, &start_threshold);
>> +
>> + /* At least one period to keep PulseAudio happy */
>> + if (start_threshold < io->period_size)
>> + start_threshold = io->period_size;
>> +
>> + pcm->buffer_attr.prebuf = start_threshold * pcm->frame_size;
>> +
>> + pa_threaded_mainloop_unlock(pcm->p->mainloop);
>> +
>> + return 0;
>> +}
>> +
>> static int pulse_close(snd_pcm_ioplug_t * io)
>> {
>> snd_pcm_pulse_t *pcm = io->private_data;
>> @@ -931,6 +957,7 @@ static const snd_pcm_ioplug_callback_t pulse_playback_callback = {
>> .poll_revents = pulse_pcm_poll_revents,
>> .prepare = pulse_prepare,
>> .hw_params = pulse_hw_params,
>> + .sw_params = pulse_sw_params,
>> .close = pulse_close,
>> .pause = pulse_pause
>> };
>> @@ -1088,6 +1115,7 @@ SND_PCM_PLUGIN_DEFINE_FUNC(pulse)
>> }
>>
>> pcm->handle_underrun = handle_underrun;
>> + pcm->buffer_attr.prebuf = -1;
>>
>> err = pulse_connect(pcm->p, server, fallback_name != NULL);
>> if (err < 0)
>> --
>> 1.7.10.4
>>
>> _______________________________________________
>> Alsa-devel mailing list
>> Alsa-devel@alsa-project.org
>> http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
>>
> _______________________________________________
> Alsa-devel mailing list
> Alsa-devel@alsa-project.org
> http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
>
--
David Henningsson, Canonical Ltd.
https://launchpad.net/~diwic
_______________________________________________
Alsa-devel mailing list
Alsa-devel@alsa-project.org
http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCHv2 1/1] pcm_pulse: set prebuf parameter according to software parameters
2012-11-20 7:51 ` David Henningsson
@ 2012-11-20 7:57 ` Takashi Iwai
0 siblings, 0 replies; 4+ messages in thread
From: Takashi Iwai @ 2012-11-20 7:57 UTC (permalink / raw)
To: David Henningsson; +Cc: alsa-devel, Rémi Denis-Courmont
At Tue, 20 Nov 2012 08:51:29 +0100,
David Henningsson wrote:
>
> On 11/19/2012 07:09 PM, Takashi Iwai wrote:
> > At Sun, 18 Nov 2012 12:01:49 +0200,
> > Rémi Denis-Courmont wrote:
> >>
> >> The current default value for prebuf is very high, almost the full
> >> virtual ALSA buffer. This breaks some application especially where
> >> low latency is involved.
> >>
> >> This patch makes pcm_pulse implement the sw_params callback and get
> >> the prebuf value from the ALSA software parameters. Thus the
> >> trigger latency is much more like what an ALSA application should
> >> expect from an ALSA PCM device.
> >
> > Looks good to me. David, could you review?
>
> I think so too.
>
> Acked-by: David Henningsson <david.henningsson@canonical.com>
OK, applied. Thanks.
Takashi
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Alsa-devel@alsa-project.org
http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
^ permalink raw reply [flat|nested] 4+ messages in thread
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2012-11-18 10:01 [PATCHv2 1/1] pcm_pulse: set prebuf parameter according to software parameters Rémi Denis-Courmont
2012-11-19 18:09 ` Takashi Iwai
2012-11-20 7:51 ` David Henningsson
2012-11-20 7:57 ` Takashi Iwai
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