topic Re: aplay (ALSA) hangs randomly when CPU frequency changes in i.MX Processors

aplay (ALSA) hangs randomly when CPU frequency changes

antonvogl — Thu, 24 Apr 2014 10:24:47 GMT

Hi,

on my battery-based i.MX28 board with SGTL5000 codec and kernel 2.6.35.3 I change the cpu frequency on the fly (for powersave purposes).

The used soundsystem is ALSA.

All works fine and I can play any wave file with "aplay".

But if the CPU frequency changes while "aplay" is playing, sometimes "aplay" stops.

In this case the status of the "aplay" process is S (sleeping).

To change the CPU frequency I use the follwoing commands:

echo performance > /sys/devices/system/cpu/cpu0/scaling_governor

echo powersave > /sys/devices/system/cpu/cpu0/scaling_governor

Any idea?

Regards

Toni

saurabh206 — Thu, 25 Dec 2014 05:11:31 GMT

Hi,

Toni

Did you able to fixed this issue?

lategoodbye — Thu, 25 Dec 2014 17:09:24 GMT

Hi Saurabh,

do you have the same problem?

Could you explain the problem a little more:

Does aplay stops forever after change frequency or does it hangs only a random amount of time?

Stefan

saurabh206 — Fri, 26 Dec 2014 03:34:14 GMT

Hi,

Stefan

We are getting system crash issue while playing short track 15ms vector in loopback mode.

[<802bc274>] (snd_pcm_period_elapsed+0x44/0xd8) from [<801a336c>] (sdma_tasklet+0x90/0x134)

[<801a336c>] (sdma_tasklet+0x90/0x134) from [<80029b00>] (tasklet_action+0x98/0xfc)

[<80029b00>] (tasklet_action+0x98/0xfc) from [<80029240>] (__do_softirq+0xd4/0x1c0)

[<80029240>] (__do_softirq+0xd4/0x1c0) from [<800293b4>] (do_softirq+0x44/0x50)

So I am trying to possible root cause behind this issue.

Saurabh

lategoodbye — Sat, 27 Dec 2014 11:36:12 GMT

Hi Saurabh,

i'm trying to port mx28 cpufreq support into Linux mainline. It would be interesting to know if the problem still occur in a current kernel version.

Unfortunately i don't a mx28 board with audio interface to test it.

Maybe you want to give it a try:

Stefan