[alsa-devel] [PATCH v2] ALSA: core: Allow drivers to set R/W wait time.
Currently ALSA core blocks userspace for about 10 seconds for PCM R/W IO. This needs to be configurable for modern hardware like DSPs where no pointer update in milliseconds can indicate terminal DSP errors.
Add a substream variable to set the wait time in ms. This allows userspace and drivers to recover more quickly from terminal DSP errors.
Signed-off-by: Liam Girdwood liam.r.girdwood@linux.intel.com ---
Changes since V1 :-
o Remove API method and alow drivers to set directly. o Validate time is driver supplied times.
include/sound/pcm.h | 1 + sound/core/pcm_lib.c | 10 ++++++++-- 2 files changed, 9 insertions(+), 2 deletions(-)
diff --git a/include/sound/pcm.h b/include/sound/pcm.h index e054c583d3b3..edad4a506b93 100644 --- a/include/sound/pcm.h +++ b/include/sound/pcm.h @@ -462,6 +462,7 @@ struct snd_pcm_substream { /* -- timer section -- */ struct snd_timer *timer; /* timer */ unsigned timer_running: 1; /* time is running */ + unsigned wait_time; /* time in ms for R/W to wait for avail */ /* -- next substream -- */ struct snd_pcm_substream *next; /* -- linked substreams -- */ diff --git a/sound/core/pcm_lib.c b/sound/core/pcm_lib.c index 44b5ae833082..6909b896a6a1 100644 --- a/sound/core/pcm_lib.c +++ b/sound/core/pcm_lib.c @@ -1832,12 +1832,18 @@ static int wait_for_avail(struct snd_pcm_substream *substream, if (runtime->no_period_wakeup) wait_time = MAX_SCHEDULE_TIMEOUT; else { - wait_time = 10; + /* use wait time from substream if available */ + if (substream->wait_time) { + wait_time = substream->wait_time; + } else { + wait_time = 10 * 1000; /* 10 secs */ + } + if (runtime->rate) { long t = runtime->period_size * 2 / runtime->rate; wait_time = max(t, wait_time); } - wait_time = msecs_to_jiffies(wait_time * 1000); + wait_time = msecs_to_jiffies(wait_time); }
for (;;) {
On Mon, 02 Jul 2018 18:04:54 +0200, Liam Girdwood wrote:
Currently ALSA core blocks userspace for about 10 seconds for PCM R/W IO. This needs to be configurable for modern hardware like DSPs where no pointer update in milliseconds can indicate terminal DSP errors.
Add a substream variable to set the wait time in ms. This allows userspace and drivers to recover more quickly from terminal DSP errors.
Signed-off-by: Liam Girdwood liam.r.girdwood@linux.intel.com
Changes since V1 :-
o Remove API method and alow drivers to set directly. o Validate time is driver supplied times.
include/sound/pcm.h | 1 + sound/core/pcm_lib.c | 10 ++++++++-- 2 files changed, 9 insertions(+), 2 deletions(-)
diff --git a/include/sound/pcm.h b/include/sound/pcm.h index e054c583d3b3..edad4a506b93 100644 --- a/include/sound/pcm.h +++ b/include/sound/pcm.h @@ -462,6 +462,7 @@ struct snd_pcm_substream { /* -- timer section -- */ struct snd_timer *timer; /* timer */ unsigned timer_running: 1; /* time is running */
- unsigned wait_time; /* time in ms for R/W to wait for avail */ /* -- next substream -- */ struct snd_pcm_substream *next; /* -- linked substreams -- */
diff --git a/sound/core/pcm_lib.c b/sound/core/pcm_lib.c index 44b5ae833082..6909b896a6a1 100644 --- a/sound/core/pcm_lib.c +++ b/sound/core/pcm_lib.c @@ -1832,12 +1832,18 @@ static int wait_for_avail(struct snd_pcm_substream *substream, if (runtime->no_period_wakeup) wait_time = MAX_SCHEDULE_TIMEOUT; else {
wait_time = 10;
/* use wait time from substream if available */if (substream->wait_time) {wait_time = substream->wait_time;} else {wait_time = 10 * 1000; /* 10 secs */}
This seems to be msec, but...
if (runtime->rate) { long t = runtime->period_size * 2 / runtime->rate; wait_time = max(t, wait_time);
... here handled as a second.
}
wait_time = msecs_to_jiffies(wait_time * 1000);
wait_time = msecs_to_jiffies(wait_time);
... so this looks inconsistent.
Also, watch out the complaints from checkpatch.pl.
thanks,
Takashi
On Mon, 02 Jul 2018 18:10:44 +0200, Takashi Iwai wrote:
On Mon, 02 Jul 2018 18:04:54 +0200, Liam Girdwood wrote:
Currently ALSA core blocks userspace for about 10 seconds for PCM R/W IO. This needs to be configurable for modern hardware like DSPs where no pointer update in milliseconds can indicate terminal DSP errors.
Add a substream variable to set the wait time in ms. This allows userspace and drivers to recover more quickly from terminal DSP errors.
Signed-off-by: Liam Girdwood liam.r.girdwood@linux.intel.com
Changes since V1 :-
o Remove API method and alow drivers to set directly. o Validate time is driver supplied times.
include/sound/pcm.h | 1 + sound/core/pcm_lib.c | 10 ++++++++-- 2 files changed, 9 insertions(+), 2 deletions(-)
diff --git a/include/sound/pcm.h b/include/sound/pcm.h index e054c583d3b3..edad4a506b93 100644 --- a/include/sound/pcm.h +++ b/include/sound/pcm.h @@ -462,6 +462,7 @@ struct snd_pcm_substream { /* -- timer section -- */ struct snd_timer *timer; /* timer */ unsigned timer_running: 1; /* time is running */
- unsigned wait_time; /* time in ms for R/W to wait for avail */ /* -- next substream -- */ struct snd_pcm_substream *next; /* -- linked substreams -- */
diff --git a/sound/core/pcm_lib.c b/sound/core/pcm_lib.c index 44b5ae833082..6909b896a6a1 100644 --- a/sound/core/pcm_lib.c +++ b/sound/core/pcm_lib.c @@ -1832,12 +1832,18 @@ static int wait_for_avail(struct snd_pcm_substream *substream, if (runtime->no_period_wakeup) wait_time = MAX_SCHEDULE_TIMEOUT; else {
wait_time = 10;
/* use wait time from substream if available */if (substream->wait_time) {wait_time = substream->wait_time;} else {wait_time = 10 * 1000; /* 10 secs */}This seems to be msec, but...
if (runtime->rate) { long t = runtime->period_size * 2 / runtime->rate; wait_time = max(t, wait_time);... here handled as a second.
}
wait_time = msecs_to_jiffies(wait_time * 1000);
wait_time = msecs_to_jiffies(wait_time);... so this looks inconsistent.
And I think we can forget runtime->rate check if it's specified explicitly. That is, something like:
/* use wait time from substream if available */ if (substream->wait_time) { wait_time = substream->wait_time; } else { wait_time = 10; /* default 10 secs */ if (runtime->rate) { long t = runtime->period_size * 2 / runtime->rate; wait_time = max(t, wait_time); } wait_time *= 1000; } wait_time = msecs_to_jiffies(wait_time * 1000);
Takashi
participants (2)
-
Liam Girdwood -
Takashi Iwai