Re: SNDRV_PCM_IOCTL_READI_FRAMES returns EIO

[Takashi Iwai <tiwai@suse.de>]

On Fri, 11 Jun 2021 12:24:40 +0200,
Muni Sekhar wrote:
> 
> On Fri, Jun 11, 2021 at 3:25 PM Takashi Iwai <tiwai@suse.de> wrote:
> >
> > On Fri, 11 Jun 2021 10:43:01 +0200,
> > Muni Sekhar wrote:
> > >
> > > On Fri, Jun 11, 2021 at 1:19 PM Takashi Iwai <tiwai@suse.de> wrote:
> > > >
> > > > On Fri, 11 Jun 2021 09:02:44 +0200,
> > > > Muni Sekhar wrote:
> > > > >
> > > > > Hi all,
> > > > >
> > > > > I am using a USB sound card(snd-usb-audio), and it fails while doing
> > > > > the audio recording "arecord: pcm_read:2032: read error: Input/output
> > > > > error".
> > > > >
> > > > >  I noticed recording(arecord) audio data on a USB sound card fails at
> > > > > SNDRV_PCM_IOCTL_READI_FRAMES is giving EIO.
> > > > >
> > > > > Can someone please clarify when the kernel returns EIO for Ioctl
> > > > > SNDRV_PCM_IOCTL_READI_FRAMES? and is there a workaround for this?
> > > >
> > > > It's a problem of either your device (e.g. USB device firmware) or the
> > > > kernel.  Do you get any relevant kernel error messages?
> > > dmesg log does not indicate any such error messages when arecord fails.
> >
> > Then it's likely a debug print in PCM core, which is suppressed as
> > default.  You can enable it via dyndbg stuff.  It won't help much for
> > diagnose at this stage, though.
> Is it snd-pcm.ko ? In my system, this module gets loaded as mentioned below:
> alsa-base.conf:15:install snd-pcm /sbin/modprobe --ignore-install
> snd-pcm $CMDLINE_OPTS && { /sbin/modprobe --quiet --use-blacklist
> snd-pcm-oss ; : ; }

The dynamic debug can be enabled at any time via sysfs.

> > > Is there a way to prove it as a USB device firmware issue or kernel issue?
> >
> > You can check strace output, for example.  The PCM core is supposed to
> > be bug-free regarding this, so it's about USB-audio driver, and the
> > problem is specific to your device (other USB-audio devices work),
> > hence it's very likely a firmware problem.
> Please find the strace output in the attached file "strace_op.txt"
> file. Does it gives any more information?

Not really for fixing the problem itself :)
Again, it's a problem in USB-audio driver, and that's likely a
firmware problem.  At best, contact with the hardware vendor.


Takashi