[Intel-gfx] [PATCH 04/12] drm/i915: Reject mixing MST and SST/HDMI on the same digital port

[Maarten Lankhorst]

Op 28-07-16 om 16:50 schreef ville.syrjala at linux.intel.com:
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
>
> We can't mix MST with SST/HDMI on the same physical port, so we'll need
> to reject such configurations in check_digital_port_conflicts(). Nothing
> else will prevent this as MST has its fake encoders and its own connectors
> so the cloning checks won't catch this.
>
> The same digital port can be used multiple times, but only if all the
> encoders involved are MST encoders, so we only want to check MST vs.
> SST/HDMI, not MST vs. MST. And SST/HDMI vs. SST/HDMI we already check.

I guess this is to prevent DP1 and DP1-2 to be both set simultaneously?
I'm not sure kms_setmode would handle this case correctly, but the idea
is correct.

Reviewed-by: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>