[PATCH] drm/i915/display/dp: Reduce log level for SOURCE OUI write failures

[Taylor, Clinton A]

On Fri, 2024-10-11 at 12:34 +0530, Pottumuttu, Sai Teja wrote:
> On 11-10-2024 03:00, Taylor, Clinton A wrote:
> > On Wed, 2024-10-09 at 22:32 +0530, Pottumuttu, Sai Teja wrote:
> > > On 05-10-2024 02:38, Clint Taylor wrote:
> > > > Some devices NAK DPCD writes to the SOURCE OUI (0x300) DPCD registers.
> > > > Reduce the log level priority to prevent dmesg noise for these devices.
> > > > 
> > > > Signed-off-by: Clint Taylor <clinton.a.taylor at intel.com>
> > > > ---
> > > >    drivers/gpu/drm/i915/display/intel_dp.c | 2 +-
> > > >    1 file changed, 1 insertion(+), 1 deletion(-)
> > > > 
> > > > diff --git a/drivers/gpu/drm/i915/display/intel_dp.c
> > > > b/drivers/gpu/drm/i915/display/intel_dp.c
> > > > index fbb096be02ad..9920ec1f9c53 100644
> > > > --- a/drivers/gpu/drm/i915/display/intel_dp.c
> > > > +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> > > > @@ -3418,7 +3418,7 @@ intel_edp_init_source_oui(struct intel_dp *intel_dp, bool
> > > > careful)
> > > >    	}
> > > >    
> > > >    	if (drm_dp_dpcd_write(&intel_dp->aux, DP_SOURCE_OUI, oui, sizeof(oui)) <
> > > > 0)
> > > > -		drm_err(&i915->drm, "Failed to write source OUI\n");
> > > > +		drm_info(&i915->drm, "Failed to write source OUI\n");
> > > >    
> > > Just had one small question here, I think NAK is one case, but in case
> > > of other errors/failures (EINVAL, ENOMEM) would we still want to reduce
> > > the log level?
> > If EINVAL or ENOMEM occurs there will be plenty of other failures earlier and later
> > that
> > will be logged. This function returns void so we don't handle any failure for
> > SourceOUI
> > write anyway. This just prevents noise in the dmesg log from known devices that NAK
> > this
> > particular DPCD operation. The other option would be to list all known devices that
> > return
> > NAK and filter them via a DCPD quirk.
> > 
> > -Clint
> Ok, in that case, should we also consider decreasing the log level of 
> read failure a little above?

Read response should never be NAK'd by the Sink device.

-Clint
 
> >    
> > > Thanks,
> > > Sai Teja
> > > 
> > > >    	intel_dp->last_oui_write = jiffies;
> > > >    }