Re: [PATCH] ASoC: lower "no backend DAIs enabled for ... Port" log severity

[Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>]

On 8/4/23 08:26, Hans de Goede wrote:
> If SNDRV_PCM_IOCTL_PREPARE is called when  the mixer settings linking
> frontend and backend have not been setup yet this results in
> e.g. the following errors getting logged:
> 
> [   43.244549]  Baytrail Audio Port: ASoC: no backend DAIs enabled for Baytrail Audio Port
> [   43.244744]  Baytrail Audio Port: ASoC: error at dpcm_fe_dai_prepare on Baytrail Audio Port: -22
> 
> pipewire triggers this leading to 96 repeats of this in the log
> after the user has logged into a GNOME session.
> 
> IMHO userspace should not be able to get the kernel to spam dmesg like
> this. Lower the severity of the "no backend DAIs enabled" log message
> for dai-s with the dynamic flag set to avoid this.
> 
> And also changes _soc_pcm_ret() to not log for -EINVAL errors, to fix
> the other error. Userspace passing wrong parameters should not lead
> to dmesg messages.

Maybe, but it's a questionable flow if pipewire tries to open stuff
without the mixer values set-up. Is there something done about this?

The reason why I am pushing back is that we had a similar issue with
HDaudio where HDMI/DP PCM devices were opened without checking if the
jack was connected.

It really makes no sense for userspace to try and open devices that are
known to be problematic. We can push kernel error logs below the rug, it
doesn't make the programming flows better.