Asking for information about ALSA's kselftest

[Mark Brown]

On Tue, Feb 22, 2022 at 01:44:27PM +0100, Giacomo Guiduzzi wrote:

> fails, and test 72. I have no previous knowledge of how ALSA works and I’m
> completely new to the kselftests and the kernel in general. Test 71 gives
> the following output:

> # Surround Playback Volume.0 expected 0 but read 1, is_volatile 0
> # Surround Playback Volume.1 expected 1 but read 0, is_volatile 0
> not ok 71 write_default.0.22

> I wanted to ask you if it is normal or not that this test fails on my
> hardware, and if not, what I could do to debug the problem and give you
> useful information to help understand what the issue is. I am currently
> testing on an Ubuntu Desktop VirtualBox VM on kernel 5.17.0-rc3. The audio
> hardware (as the output of the lshw command, multimedia section) is:

That shouldn't happen - it will be a driver specific issue of some kind,
either a bug in the driver itself or needing to work around some issue
with the hardware (emulated hardware in your case).  The core ALSA code
pretty much just passes these operations straight through to the drivers.

> From what I have seen until now it doesn’t look like a bug from the test nor
> an issue from the kernel, so I’m not really sure where to look at: I have

As far as I can see it's a kernel or lower issue - userspace wrote a
value that's valid for the control but read back a different value (if I
had to guess I'd say the left and right channels are getting confused on
either the read or the write).
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 488 bytes
Desc: not available
URL: <http://mailman.alsa-project.org/pipermail/alsa-devel/attachments/20220222/ff74b6e6/attachment.sig>