[alsa-devel] alsa-utils aplay/arecord can't be interrupted when streaming is not active

Jaroslav Kysela perex at perex.cz
Wed Apr 16 10:58:40 CEST 2014

Date 16.4.2014 10:34, jiwang wrote:
> Hi Jaroslav
> On 04/16/2014 05:06 PM, Jaroslav Kysela wrote:
>> Date 16.4.2014 09:54, jiwang wrote:
>>> Hi All
>>> With latest alsa-utils, I am facing problem to interrupt
>>> aplay/arecord
>>> when the streaming is not active (no data can be written to or read from
>>> cards)
>>> further more, if I start aplay/arecord with "-N" nonblocking option,
>>> then aplay/arecord can never exit, unless I do a system reset
>> If I/O stalls it's usually problem in the driver. You don't write any
>> information about your configuration - post 'aplay -v' to see more.
> This issue is caught when we were doing some tests,
> test for both correct and incorrect configuration of driver
> and we expect SIGINT can interrupt aplay/arecord in both cases
> (which was the cause with the old version 1.0.26)
>> You may kill the process using the SIGABRT signal.. No reboot is required.
> Yes, SIGABRT works,
> But as in our case:
> CPU dai device is waiting on a external clock,
> but isnt provided caused the I/O stall
> the driver is functioning properly and should still be SIGINT-ed in my 
> opinion

The user space received SIGINT, but the current aplay code tries to
finish the device close sequence. Could you determine, in which syscall
is the process after you sent SIGINT? A backtrace would be great.

> Thanks,
> Jiada
>>> I found if I revert the following patch
>>> /commit 1d0042d7e948815f8015c62bc53143eed3b83206//
>>> //Author: Jaroslav Kysela <perex at perex.cz>//
>>> //Date:   Mon Apr 8 13:30:54 2013 +0200//
>>> //
>>> //    aplay/arecord: change the interrupt handling using snd_pcm_abort()//
>>> //    //
>>> //    It is required (exclude the fatal SIGABRT) to call snd_pcm_close()
>>> and//
>>> //    the end of work (outside of the interrupt handler). Use new
>>> snd_pcm_abort()//
>>> //    function to inform alsa-lib to not ignore EINTR and move the
>>> in_aborting//
>>> //    variable to the global scope to be checked in the i/o loops.//
>>> //    //
>>> //    Signed-off-by: Jaroslav Kysela <perex at perex.cz>//
>>> /
>>> http://git.alsa-project.org/?p=alsa-utils.git;a=commit;h=1d0042d7e948815f8015c62bc53143eed3b83206
>>> then aplay/arecord can be interrupted correctly
>>> Is it a defect in aplay.c or did I miss something?
>>> Thanks,
>>> Jiada

Jaroslav Kysela <perex at perex.cz>
Linux Kernel Sound Maintainer
ALSA Project; Red Hat, Inc.

More information about the Alsa-devel mailing list