[Intel-gfx] [PATCH] drm/i915: Tune down WARN about incorrect VBT TC legacy flag

[Imre Deak]

On Fri, May 03, 2019 at 02:35:59PM +0200, Daniel Vetter wrote:
> On Thu, May 02, 2019 at 03:09:00PM +0300, Jani Nikula wrote:
> > On Thu, 02 May 2019, Imre Deak <imre.deak at intel.com> wrote:
> > > Looks like VBT contains again the wrong information about a port's TypeC
> > > legacy vs. DP-alt/TBT-alt type. There is no further issues after we
> > > notice this and fix it up, so tune down the WARN to be a a DRM_ERROR.
> > >
> > > This also avoids CI tainting the kernel and stopping the test run.
> > >
> > > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=110578
> > > Cc: Jani Nikula <jani.nikula at intel.com>
> > > Signed-off-by: Imre Deak <imre.deak at intel.com>
> > > ---
> > >  drivers/gpu/drm/i915/intel_dp.c | 7 +++++--
> > >  1 file changed, 5 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> > > index 4e7b8d29d733..07fa2670a677 100644
> > > --- a/drivers/gpu/drm/i915/intel_dp.c
> > > +++ b/drivers/gpu/drm/i915/intel_dp.c
> > > @@ -5230,9 +5230,12 @@ static bool icl_tc_port_connected(struct drm_i915_private *dev_priv,
> > >  	 * WARN if we got a legacy port HPD, but VBT didn't mark the port as
> >            ^^^^
> > 
> > With the comment fixed,
> > 
> > Reviewed-by: Jani Nikula <jani.nikula at intel.com>
> > 
> > >  	 * legacy. Treat the port as legacy from now on.
> > >  	 */
> > > -	if (WARN_ON(!intel_dig_port->tc_legacy_port &&
> > > -		    I915_READ(SDEISR) & SDE_TC_HOTPLUG_ICP(tc_port)))
> > > +	if (!intel_dig_port->tc_legacy_port &&
> > > +	    I915_READ(SDEISR) & SDE_TC_HOTPLUG_ICP(tc_port)) {
> > > +		DRM_ERROR("VBT incorrectly claims port %c is not TypeC legacy\n",
> > > +			  port_name(port));
> > >  		intel_dig_port->tc_legacy_port = true;
> 
> DRM_ERRROR still causes CI failures (e.g. module reload, where I guess
> this ends up in the logs).
> 
> If we really can fully fix it up I think a DRM_INFO is the right level.

We have to wait until the first legacy HPD interrupt, whereas with a
correct VBT info we would configure the correct mode right from the
start. So I think it's still a problem and we should be complaining
about it louder even later.

I filed an HSD for it and would hope it would be treated as a real issue
by that team, not just yet another HSD. For that reason too I'd go
keeping it as an error, not to lose it from the radar.

Meanwhile, the error message is very specific (about this particular port
and scenario) so I think CI filtering could cope with marking it as a
known issue, until we get it fixed in VBT.

> -Daniel
> 
> > > +	}
> > >  	is_legacy = intel_dig_port->tc_legacy_port;
> > >  
> > >  	/*
> > 
> > -- 
> > Jani Nikula, Intel Open Source Graphics Center
> > _______________________________________________
> > Intel-gfx mailing list
> > Intel-gfx at lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/intel-gfx
> 
> -- 
> Daniel Vetter
> Software Engineer, Intel Corporation
> http://blog.ffwll.ch