[Intel-gfx] [PATCH 11/14] drm/i915: Fix DP-MST crtc_mask

[Dhinakaran Pandiyan]

On Fri, 2018-06-15 at 21:43 +0300, Ville Syrjälä wrote:
> On Fri, Jun 15, 2018 at 11:33:01AM -0700, Dhinakaran Pandiyan wrote:
> > 
> > On Fri, 2018-06-15 at 19:49 +0300, Ville Syrjala wrote:
> > > 
> > > From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> > > 
> > > Each fake MST encoder is tied to a specific pipe. Fix the
> > > encoder's
> > > crtc_mask to reflect that fact.
> > > 
> > > Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> > > ---
> > >  drivers/gpu/drm/i915/intel_dp_mst.c | 2 +-
> > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > > 
> > > diff --git a/drivers/gpu/drm/i915/intel_dp_mst.c
> > > b/drivers/gpu/drm/i915/intel_dp_mst.c
> > > index 5890500a3a8b..8e30765402b4 100644
> > > --- a/drivers/gpu/drm/i915/intel_dp_mst.c
> > > +++ b/drivers/gpu/drm/i915/intel_dp_mst.c
> > > @@ -565,7 +565,7 @@ intel_dp_create_fake_mst_encoder(struct
> > > intel_digital_port *intel_dig_port, enum
> > >  	intel_encoder->type = INTEL_OUTPUT_DP_MST;
> > >  	intel_encoder->power_domain = intel_dig_port-
> > > > 
> > > > base.power_domain;
> > >  	intel_encoder->port = intel_dig_port->base.port;
> > > -	intel_encoder->crtc_mask = 0x7;
> > > +	intel_encoder->crtc_mask = BIT(pipe);
> > How did this not cause any problems? Does this mean this field
> > was/is
> > unused?
> This is a hint to userspace. So userspace would pick the connector
> and crtc based on the hints, and then the kernel gets to pick the
> actual encoder. In this case the bogus hint was good enough to tell
> userspace that it can pick any crtc for any MST connector.
> 
> Hmm. Why on earth do we have .atomic_best_encoder() and
> .best_encoder()
> for MST? The fb_helper appears to want to use the non-atomic one for
> some reason... On boy, I guess I'll need to do something about that.
> As is this patch would probably break it :(
> 
So we end up picking crtc-0 for all MST connectors with the same
primary.

Since this patch does the right thing and assuming
https://patchwork.freedesktop.org/patch/229905/ gets merged before this

Reviewed-by: Dhinakaran Pandiyan <dhinakaran.pandiyan at intel.com>