Hi Takashi Iwai, Jaroslav Kysela
We found an issue on dmix in alsa-lib when do suspend and resume. It can be easily reproduced by following steps:
1. Run two dmix clients in parallel. (Only one client doesn't has such issue)
~# aplay xxx1.wav &
~# aplay xxx2.wav &
Here I attach the asound.conf we're using.
~# cat /etc/asound.conf
defaults.pcm.rate_converter "linear"
pcm.dmix_44100{
type dmix
ipc_key 5678293
ipc_key_add_uid yes
slave{
pcm "hw:0,0"
period_time 40000
format S16_LE
rate 44100
}
}
pcm.asymed{
type asym
playback.pcm "dmix_44100"
capture.pcm "dsnoop_44100"
}
pcm.!default{
type plug
route_policy "average"
slave.pcm "asymed"
}
2. Let linux enter into suspend and then resume(Repeat this step if not reproduced)
3. After resume, aplay will get stuck in snd_pcm_wait(). The GDB shows:
(gdb) bt
#0 0x0000fffff7da9264 in __GI___poll (fds=fds@entry=0xfffffffff480, nfds=nfds@entry=1, timeout=timeout@entry=240)
at /usr/src/debug/glibc/2.39+git/sysdeps/unix/sysv/linux/poll.c:41
#1 0x0000fffff7edf468 in poll (__timeout=240, __nfds=1, __fds=0xfffffffff480)
#2 snd1_pcm_wait_nocheck (pcm=pcm@entry=0xaaaaaaad2cb0, timeout=240, timeout@entry=-10001) at pcm.c:2993
#3 0x0000fffff7ee54a0 in snd1_pcm_write_areas (pcm=pcm@entry=0xaaaaaaad2cb0, areas=areas@entry=0xfffffffff560, offset=<optimized out>, offset@entry=0, size=<optimized out>,
size@entry=1768, func=func@entry=0xfffff7ef5190 <snd_pcm_plugin_write_areas>) at pcm.c:7699
#4 0x0000fffff7ef5020 in snd_pcm_plugin_writei (pcm=0xaaaaaaad2cb0, buffer=<optimized out>, size=1768) at pcm_plugin.c:354
It seems that sometimes after suspend and resume there's no available space for data written into buffer. Then aplay keeps stuck in snd_pcm_wait(). I checked the hw_ptr of dmix and found that hw_ptr is always 0 after resume.
I don't have a solution now so I turn to you for help. The version of alsa-lib is v1.2.11. Could you please help check it?
Regards,
Chancel Liu
