[Intel-gfx] [PATCH] drm/i915: Sink CRC: tune down error message at stop to debug_kms.

[Zanoni, Paulo R]

Em Ter, 2016-01-19 às 22:21 +0000, Vivi, Rodrigo escreveu:
> On Tue, 2016-01-19 at 17:46 +0000, Zanoni, Paulo R wrote:
> > Em Qua, 2016-01-13 às 14:05 -0800, Rodrigo Vivi escreveu:
> > > When we stop the sink CRC calculation we wait a while until the
> > > counter
> > > is reset to zero and return -ETIMEDOUT. However the sink crc was
> > > calculated already by this point so we just ignore this return at
> > > the main function.
> > > 
> > > So, let's also ignore the message and put it as a debug message
> > > instead
> > > of an error one. The message might still be useful when debuging
> > > test failures so we could be able to know something was not
> > > going 
> > > so
> > > well with sink crc stop.
> > > Reference: https://bugs.freedesktop.org/show_bug.cgi?id=93694
> > > Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
> > > Cc: Paulo Zanoni <paulo.r.zanoni at intel.com>
> > > Signed-off-by: Rodrigo Vivi <rodrigo.vivi at intel.com>
> > > ---
> > >  drivers/gpu/drm/i915/intel_dp.c | 2 +-
> > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > > 
> > > diff --git a/drivers/gpu/drm/i915/intel_dp.c
> > > b/drivers/gpu/drm/i915/intel_dp.c
> > > index c8f58ab..22f6887 100644
> > > --- a/drivers/gpu/drm/i915/intel_dp.c
> > > +++ b/drivers/gpu/drm/i915/intel_dp.c
> > > @@ -4009,7 +4009,7 @@ static int intel_dp_sink_crc_stop(struct
> > > intel_dp *intel_dp)
> > >  	} while (--attempts && count);
> > 
> > Now I'm wondering if "count" stays static or changes during the 10
> > failed attempts. I know this is against the spec, but would make
> > some
> > sense to see it.
> > 
> > Another possibility is that we're not changing the contents of the
> > frame, so maybe we need to give it something new in order for the 
> > count
> > to really reset. This would make more sense for PSR.
> 
> Well, on the machines that sink crc isn't reliable I tried many
> attempts like to change the screen content, enable and disable again,
> sait more time, etc and there is no reliable way to make sure it
> reset
> to zero. Sometimes it just keep increasing even with test zeroed... 
> not following dp spec at all... 
> 
> > 
> > Anyway, this "error" shouldn't be a problem for our test suite. If
> > it
> > impacts the next CRC calculations, then we'll notice this through 
> > other
> > means, so:
> > Reviewed-by: Paulo Zanoni <paulo.r.zanoni at intel.com>
> 
> Thanks, but on IRC daniel had complained that the message is not good
> for debug purpose. So before merging it I'd like to check with you if
> it would be better with something like:
> 
> DRM_DEBUG_KMS("TIMEOUT: Sink CRC counter is not zeroed after
> calculation is stopped\n");

Since he's the one doing the suggestion, I'll let him answer.

> 
> ?
> 
> > 
> > >  
> > >  	if (attempts == 0) {
> > > -		DRM_ERROR("TIMEOUT: Sink CRC counter is not
> > > zeroed\n");
> > > +		DRM_DEBUG_KMS("TIMEOUT: Sink CRC counter is not
> > > zeroed\n");
> > >  		ret = -ETIMEDOUT;