[Intel-gfx] [PATCH v2] drm/i915: Only check eDP HPD when AUX CH is shared

[Coelho, Luciano]

On Fri, 2023-09-08 at 08:25 +0300, Ville Syrjala wrote:
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> 
> Apparently Acer Chromebook C740 (BDW-ULT) doesn't have the
> eDP HPD line properly connected, and thus fails the new
> HPD check during eDP probe. The result is that we lose the
> eDP output.
> 
> I suspect all such machines would all be Chromebooks or other

Small duplication here "...all such machines would all...".


> Linux exclusive systems as the Windows driver likely wouldn't
> work either. I did check a few other BDW machines here and
> those do have eDP HPD connected, one of them even is a
> different Chromebook (Samus).
> 
> To account for these funky machines let's skip the HPD check when
> it looks like the eDP port is the only one using that specific AUX
> channel. In case of multiple ports sharing the same AUX CH (eg. on
> Asrock B250M-HDV) we still do the check and thus should correctly
> ignore the eDP port in favor of the other DP port (usually a DP->VGA
> converter).
> 
> v2: Don't oops during list iteration
> 
> Cc: stable at vger.kernel.org
> Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/9264
> Fixes: cfe5bdfb27fa ("drm/i915: Check HPD live state during eDP probe")
> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> ---

Regardless of the small grammatical issue, LGTM:

Reviewed-by: Luca Coelho <luciano.coelho at intel.com>

--
Cheers,
Luca.