alsa: reread configuration when opening new devices

If a card has been hot-plugged after pulseaudio start, alsa-lib still has
old configuration in memory, which doesn't have PCM definitions for the
new card. Thus, this error appears, and the device doesn't work:

I: [pulseaudio] (alsa-lib)confmisc.c: Unable to find definition 'cards.USB-Audio.pcm.front.0:CARD=0'
I: [pulseaudio] (alsa-lib)conf.c: function snd_func_refer returned error: No such file or directory
I: [pulseaudio] (alsa-lib)conf.c: Evaluate error: No such file or directory
I: [pulseaudio] (alsa-lib)pcm.c: Unknown PCM front:0
I: [pulseaudio] alsa-util.c: Error opening PCM device front:0: No such file or directory

The snd_config_update_free_global() function makes alsa-lib forget any
cached configuration and reparse all PCM definitions from scratch next
time it is told to open anything.

The trick has been copied from Phonon.

Fixes: https://bugs.freedesktop.org/show_bug.cgi?id=54029
Signed-off-by: Alexander E. Patrakov <patrakov@gmail.com>
This commit is contained in:
Alexander E. Patrakov 2016-05-22 02:03:21 +05:00 committed by Arun Raghavan
parent 4c42b3ef7c
commit 768c80f3c3
3 changed files with 26 additions and 0 deletions

View file

@ -1854,6 +1854,15 @@ pa_source *pa_alsa_source_new(pa_module *m, pa_modargs *ma, const char*driver, p
b = use_mmap;
d = use_tsched;
/* Force ALSA to reread its configuration if module-alsa-card didn't
* do it for us. This matters if our device was hot-plugged after ALSA
* has already read its configuration - see
* https://bugs.freedesktop.org/show_bug.cgi?id=54029
*/
if (!card)
snd_config_update_free_global();
if (mapping) {
if (!(dev_id = pa_modargs_get_value(ma, "device_id", NULL))) {