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

[Takashi Iwai <tiwai@suse.de>]

On Fri, 04 Aug 2023 17:15:14 +0200,
Mark Brown wrote:
> 
> On Fri, Aug 04, 2023 at 04:42:34PM +0200, Takashi Iwai wrote:
> > Pierre-Louis Bossart wrote:
> 
> > > > 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?
> 
> > I think it's an oft-seen problem when user runs the system without
> > installing a proper UCM profile.
> 
> Yeah, it's really easy to do.
> 
> > > 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.
> 
> > Downgrading the message also hides to show what's wrong there.
> > Although the message doesn't indicate how to fix the problem, no
> > message would make debug harder.
> 
> > So in general I agree that it's annoying and it should be fixed, but
> > hiding all as default can be bad, too.  Maybe we can introduce a
> > counter and shut out after three strikes?
> 
> Hrm, do systems typically filter out debug logs?  Most of the systems I
> work on do still log debug logs, they just only include them in dmesg by
> default.

I thought flipping the dynamic debug flag needed for showing them up
with dev_dbg() and co.

> There are ratelimited printk APIs which we could use, though
> they're not quite ratelimited enough for this I think.

Yes, this is printed not too frequently but just repeatedly.

IMHO, dev_err_once() would be a good compromise.


thanks,

Takashi