From ede8cbb131f7493f14f5717aefd5b4e0603a05d1 Mon Sep 17 00:00:00 2001 From: Hui Wang Date: Thu, 9 Jul 2020 10:48:33 +0800 Subject: [PATCH] alsa: make the unsuspend more robust We met a weird situation on a couple of Lenovo machines and at least on one Dell machine. First we open the gnome-sound-setting, then suspend and resume the system, after the system resume back, the audio devices change to dummy, the audio doesn't work anymore. And pacmd list-cards shows no available sound card. Through debugging I found after resume, the alsa receives POLLERR events and it will call unsuspend to recover the pcm, but at that moment, the device nodes in /dev/snd/ is not accessible, so the snd_pcm_open() fails and the pulseaudio unload the module-alsa-card. Here I add retry and pa_msleep if snd_pcm_open fails, I tested it on all machines which have this problem, pa_msleep(25) is ok for most of them, there is only one machine which needs to call pa_msleep(25) twice, so for safety reason, I set the max retry times to 4. Signed-off-by: Hui Wang --- src/modules/alsa/alsa-sink.c | 29 +++++++++++++++++++++-------- src/modules/alsa/alsa-source.c | 27 ++++++++++++++++++++------- 2 files changed, 41 insertions(+), 15 deletions(-) diff --git a/src/modules/alsa/alsa-sink.c b/src/modules/alsa/alsa-sink.c index 67523f1c9..457dc2785 100644 --- a/src/modules/alsa/alsa-sink.c +++ b/src/modules/alsa/alsa-sink.c @@ -1152,7 +1152,7 @@ static void update_size(struct userdata *u, pa_sample_spec *ss) { /* Called from IO context */ static int unsuspend(struct userdata *u, bool recovering) { pa_sample_spec ss; - int err; + int err, i; bool b, d; snd_pcm_uframes_t period_frames, buffer_frames; snd_pcm_uframes_t tsched_frames = 0; @@ -1172,13 +1172,26 @@ static int unsuspend(struct userdata *u, bool recovering) { pa_snprintf(device_name, len, "%s,AES0=6", u->device_name); } - if ((err = snd_pcm_open(&u->pcm_handle, device_name ? device_name : u->device_name, SND_PCM_STREAM_PLAYBACK, - SND_PCM_NONBLOCK| - SND_PCM_NO_AUTO_RESAMPLE| - SND_PCM_NO_AUTO_CHANNELS| - SND_PCM_NO_AUTO_FORMAT)) < 0) { - pa_log("Error opening PCM device %s: %s", u->device_name, pa_alsa_strerror(err)); - goto fail; + /* + * On some machines, during the system suspend and resume, the thread_func could receive + * POLLERR events before the dev nodes in /dev/snd/ are accessible, and thread_func calls + * the unsuspend() to try to recover the PCM, this will make the snd_pcm_open() fail, here + * we add msleep and retry to make sure those nodes are accessible. + */ + for (i = 0; i < 4; i++) { + if ((err = snd_pcm_open(&u->pcm_handle, device_name ? device_name : u->device_name, SND_PCM_STREAM_PLAYBACK, + SND_PCM_NONBLOCK| + SND_PCM_NO_AUTO_RESAMPLE| + SND_PCM_NO_AUTO_CHANNELS| + SND_PCM_NO_AUTO_FORMAT)) < 0 && recovering) + pa_msleep(25); + else + break; + } + + if (err < 0) { + pa_log("Error opening PCM device %s: %s", u->device_name, pa_alsa_strerror(err)); + goto fail; } if (pa_frame_size(&u->sink->sample_spec) != u->frame_size) { diff --git a/src/modules/alsa/alsa-source.c b/src/modules/alsa/alsa-source.c index 4b134d85c..da99ac610 100644 --- a/src/modules/alsa/alsa-source.c +++ b/src/modules/alsa/alsa-source.c @@ -1033,7 +1033,7 @@ static void update_size(struct userdata *u, pa_sample_spec *ss) { /* Called from IO context */ static int unsuspend(struct userdata *u, bool recovering) { pa_sample_spec ss; - int err; + int err, i; bool b, d; snd_pcm_uframes_t period_frames, buffer_frames; snd_pcm_uframes_t tsched_frames = 0; @@ -1044,12 +1044,25 @@ static int unsuspend(struct userdata *u, bool recovering) { pa_log_info("Trying resume..."); - if ((err = snd_pcm_open(&u->pcm_handle, u->device_name, SND_PCM_STREAM_CAPTURE, - SND_PCM_NONBLOCK| - SND_PCM_NO_AUTO_RESAMPLE| - SND_PCM_NO_AUTO_CHANNELS| - SND_PCM_NO_AUTO_FORMAT)) < 0) { - pa_log("Error opening PCM device %s: %s", u->device_name, pa_alsa_strerror(err)); + /* + * On some machines, during the system suspend and resume, the thread_func could receive + * POLLERR events before the dev nodes in /dev/snd/ are accessible, and thread_func calls + * the unsuspend() to try to recover the PCM, this will make the snd_pcm_open() fail, here + * we add msleep and retry to make sure those nodes are accessible. + */ + for (i = 0; i < 4; i++) { + if ((err = snd_pcm_open(&u->pcm_handle, u->device_name, SND_PCM_STREAM_CAPTURE, + SND_PCM_NONBLOCK| + SND_PCM_NO_AUTO_RESAMPLE| + SND_PCM_NO_AUTO_CHANNELS| + SND_PCM_NO_AUTO_FORMAT)) < 0 && recovering) + pa_msleep(25); + else + break; + } + + if (err < 0) { + pa_log("Error opening PCM device %s: %s", u->device_name, pa_alsa_strerror(err)); goto fail; }