Re: ASoC q6asm race condition when stopping and preparing the stream

[Val Packett]

Hi,

On 5/1/26 8:53 PM, Richard Acayan wrote:
> On Fri, May 01, 2026 at 04:27:57PM +0100, Alexey Klimov wrote:
> > On Fri May 1, 2026 at 3:41 PM BST, Richard Acayan wrote:
> > > Hi,
> > >
> > > There seems to be a race condition in q6asm when stopping the stream
> > > (with uncompressed PCM). When receiving SNDRV_PCM_TRIGGER_STOP, the
> > > driver sets the state to Q6ASM_STREAM_STOPPED and sends CMD_EOS to the
> > > ADSP. If userspace decides to prepare the stream again in
> > > q6asm_dai_prepare before receiving ASM_CLIENT_EVENT_CMD_EOS_DONE, the
> > > memory-mapped region appears to still be in use and fails to map again.
> > >
> > > I believe this race was observed since commit 81c53b52de21 ("ASoC: qcom:
> > > qdsp6: q6asm-dai: set 10 ms period and buffer alignment."), but would
> > > need to verify. On sdm670, we are coping downstream by keeping the state
> > > as Q6ASM_STREAM_RUNNING until receiving CMD_EOS_DONE.
Are we sure that's only a workaround and not the correct solution?
Thank you for mentioning it, in any case!
> > Do you have a reproducer or specific steps to test/reproduce the issue?
> I don't really have an easy way to reproduce. On a device with a
> Qualcomm SoC and q6asm, running postmarketOS with Phosh and without the
> workaround, waiting a few hours usually reproduces it.

I haven't seen this happen "randomly".. at least not with PulseAudio, 
but after switching to PipeWire and properly configuring phone calls(*) 
on my phone (sm7325-motorola-dubai) I have encountered what I think is 
the exact same issue many times while doing this simple sequence:

- boot phone, playback and recording work fine
- start a phone call, cancel when hearing dial tone (Wireplumber has 
switched UCM profile to VoiceCall and then back to HiFi)
- try to record mic sound (using the GNOME sound recorder app or 
whatever else)

Actually just now I managed to hit this right after reboot, without any 
calls..!

So it might just be "try to record audio through PipeWire and you'll hit 
it quickly enough".


(*) using the current infamous q6voice patchset, Wireplumber's script to 
switch between HiFi/VoiceCall, and a better setup for starting the dummy 
streams exposed by q6voice: 
https://gitlab.postmarketos.org/postmarketOS/q6voiced/-/work_items/3#note_553107

The log is usually something like this:

kernel: q6asm-dai 3700000.remoteproc:glink-edge:apr:service@7:dais: 
Buffer already allocated
kernel: q6asm-dai 3700000.remoteproc:glink-edge:apr:service@7:dais: cmd 
= 0x10db4 returned error = 0x9
kernel: q6asm-dai 3700000.remoteproc:glink-edge:apr:service@7:dais: DSP 
returned error[9]
pipewire[5347]: [E][02:30:35.781627] spa.alsa     | [ alsa-pcm.c: 2722 
do_prepare()] hw:Motoroladubai,2c: snd_pcm_prepare error: Invalid argument
pipewire[5347]: [W][02:30:35.781714] spa.alsa     | [ alsa-pcm.c: 2885 
get_avail()] hw:Motoroladubai,2c: (0 suppressed) snd_pcm_avail after 
recover: File desc>
pipewire[5347]: [E][02:30:35.781771] spa.alsa     | [ alsa-pcm.c: 2832 
alsa_recover()] hw:Motoroladubai,2c: recover from error state SETUP
pipewire[5347]: [E][02:30:35.781801] spa.alsa     | [ alsa-pcm.c: 2722 
do_prepare()] hw:Motoroladubai,2c: snd_pcm_prepare error: Invalid argument
pipewire[5347]: [E][02:30:35.781821] spa.alsa     | [ alsa-pcm.c: 2832 
alsa_recover()] hw:Motoroladubai,2c: recover from error state SETUP
pipewire[5347]: [E][02:30:35.781837] spa.alsa     | [ alsa-pcm.c: 2722 
do_prepare()] hw:Motoroladubai,2c: snd_pcm_prepare error: Invalid argument
pipewire[5347]: [E][02:30:35.786869] spa.alsa     | [ alsa-pcm.c: 2832 
alsa_recover()] hw:Motoroladubai,2c: recover from error state SETUP
pipewire[5347]: [E][02:30:35.786949] spa.alsa     | [ alsa-pcm.c: 2722 
do_prepare()] hw:Motoroladubai,2c: snd_pcm_prepare error: Invalid argument
kernel: q6asm-dai 3700000.remoteproc:glink-edge:apr:service@7:dais: 
q6asm_dai_prepare: q6asm_open_write failed
kernel: q6asm-dai 3700000.remoteproc:glink-edge:apr:service@7:dais: ASoC 
error (-22): at snd_soc_pcm_component_prepare() on 
3700000.remoteproc:glink-edge:apr:servi>
kernel: q6asm-dai 3700000.remoteproc:glink-edge:apr:service@7:dais: 
q6asm_dai_prepare: private data null or audio client freed
kernel: q6asm-dai 3700000.remoteproc:glink-edge:apr:service@7:dais: ASoC 
error (-22): at snd_soc_pcm_component_prepare() on 
3700000.remoteproc:glink-edge:apr:servi>
kernel: q6asm-dai 3700000.remoteproc:glink-edge:apr:service@7:dais: 
q6asm_dai_prepare: private data null or audio client freed
…

"Buffer already allocated", error 9 which is ADSP_EALREADY, so the state 
is desynchronized.


Thanks,
~val