Re: [PATCH 1/1] ASoC: core: Do not print an actual error when deferring probe

[Alexander Stein <alexander.stein@systec-electronic.com>]

On Wednesday 18 May 2016 21:33:01, Takashi Iwai wrote:
> On Wed, 18 May 2016 19:20:19 +0200,
> 
> Mark Brown wrote:
> > On Wed, May 18, 2016 at 06:57:50PM +0200, Takashi Iwai wrote:
> > > Mark Brown wrote:
> > > > It's just shifting the problem around...  it sounds like for your use
> > > > case suppressing the messages until we finish kernel boot would deal
> > > > with most of the issue in a far more general fashion.
> > > 
> > > It comes to the question whether this message must be shown verbosely
> > > as an error at all.  EPROBE_DEFER is usually a mechanism for the
> > > delayed probe, and it doesn't indicate an error per se.  dev_err() is,
> > > OTOH, for real errors that have to be notified to user inevitably.
> > > That's why "quiet" boot option still shows it.
> > 
> > We can't tell the difference between something that's delayed and will
> > come up later and something that's just never going to work - missing
> > or misidentified components has always been a common source of errors
> > in ASoC device bringup.
> 
> Yes, but it still means that most of cases are false-positive to show
> as "error" message.

I think the same way. Of course it is an error if probing never finishes due 
to some missing configuration/dt entry, but that needs to be checked in dmesg 
anyway. dev_notice still allows that.

> > There's also just the fact that the noise from
> > deferred probe is not an ASoC specific thing, we need to tackle this at
> > a system level rather than hacking individual cases.
> 
> Such other noises are usually now shown as errors with dev_err() but
> with dev_*() with a lower level.
> 
> I guess the patch subject and description are misleading.  This
> doesn't suppress the messages to be printed.  In usual boots without
> quiet boot option, there will be no visible change with this patch,
> the messages are still shown.  It's not shown, however, when booted
> with quiet boot option.  That's the whole point.
> 
> dev_notice() lowers the log level to somewhat between info and
> warning, and it looks like a sensible choice to me.

You want me to change the subject to be more clear?

Regards,
Alexander