[Intel-gfx] [PATCH 0/3] Propagate DP-over-Type-C hotplug events from Type-C subsys to drm-drivers

[Jani Nikula]

On Wed, 27 Feb 2019, Heikki Krogerus <heikki.krogerus at linux.intel.com> wrote:
> One thing that this series does not consider is the DP lane count
> problem. The GPU drivers (i915 in this case) does not know is four,
> two or one DP lanes in use.

Also, orientation.

> I guess that is not a critical issue since there is a workaround (I
> think) where the driver basically does trial and error, but ideally we
> should be able to tell i915 also the pin assignment that was
> negotiated with the partner device so it knows the DP lane count.

Yeah, if the information is there, we'd like to know. With the
orientation, there's a worst case of sixth attempt of finding out
there's just one lane in a certain orientation. Couple that with link
rate selection (did it not work because too high link rate or because
the lanes are just not there?) we get pretty confused about what we
should try.

BR,
Jani.


-- 
Jani Nikula, Intel Open Source Graphics Center