[Intel-gfx] [PATCH 11/12] drm/i915: WARN if a port should use VBT provided vswing tables

[Ville Syrjälä]

On Tue, Jul 19, 2022 at 06:31:11AM -0400, Rodrigo Vivi wrote:
> On Fri, Jul 15, 2022 at 11:20:43PM +0300, Ville Syrjala wrote:
> > From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> > 
> > We don't parse the VBT vswing/preemphassis tables at all currently.
> > Let's WARN if a port wants to use them so we get a heads up that
> > whether we really need to implement this stuff or not. My
> > current stash contains no VBTs with this bit set.
> 
> let's unlock a new can of worms?! :)
> 
> I believe this deserves a /* XXX: comment with the code in case
> someone else finds this warns first and doesn't use the git blame

Sure I'll stick some kind of comment there.

> 
> anyways
> Reviewed-by: Rodrigo Vivi <rodrigo.vivi at intel.com>
> 
> > 
> > Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> > ---
> >  drivers/gpu/drm/i915/display/intel_bios.c | 4 ++++
> >  1 file changed, 4 insertions(+)
> > 
> > diff --git a/drivers/gpu/drm/i915/display/intel_bios.c b/drivers/gpu/drm/i915/display/intel_bios.c
> > index 51dde5bfd956..cd86b65055ef 100644
> > --- a/drivers/gpu/drm/i915/display/intel_bios.c
> > +++ b/drivers/gpu/drm/i915/display/intel_bios.c
> > @@ -2661,6 +2661,10 @@ static void parse_ddi_port(struct intel_bios_encoder_data *devdata)
> >  		return;
> >  	}
> >  
> > +	drm_WARN(&i915->drm, child->use_vbt_vswing,
> > +		 "Port %c asks to use VBT vswing/preemph tables\n",
> > +		 port_name(port));
> > +
> >  	if (i915->vbt.ports[port]) {
> >  		drm_dbg_kms(&i915->drm,
> >  			    "More than one child device for port %c in VBT, using the first.\n",
> > -- 
> > 2.35.1
> > 

-- 
Ville Syrjälä
Intel