[Intel-gfx] [PATCH 4/5] drm/i915: use current mode if the size matches the preferred mode

[Jesse Barnes]

On Tue, 10 Jun 2014 16:05:36 +0200
Daniel Vetter <daniel at ffwll.ch> wrote:

> On Thu, Jun 05, 2014 at 11:24:30AM -0700, Jesse Barnes wrote:
> > From: Kristian Høgsberg <hoegsberg at gmail.com>
> > 
> > The BIOS may set a native mode that doesn't quite match the preferred
> > mode timings.  It should be ok to use however if it uses the same size,
> > so try to avoid a mode set in that case.
> > 
> > Signed-off-by: Kristian Høgsberg <hoegsberg at gmail.com>
> > Signed-off-by: Jesse Barnes <jbarnes at virtuousgeek.org>
> 
> Not sure we want this since this seems to override the cmdline options to
> force a specific edid. Also not sure whether we shouldn't just add this as
> the preferred mode when probing (before the preferred mode the vbt/edid
> provides ofc).
> 
> What exactly is the mismatch here? It could be DRRS or something fancy,
> too.
> 
> Not sure what to do here really.

AFAICT it's just slightly different timings for fun.  I don't think
they go low enough to reduce the DP lane count... maybe there's just a
mismatch between their hard coded panel timings and the ones reported
by the EDID.  Not sure which to trust...  Kristian can you post the
timings you see here?  Both the BIOS timings and the EDID ones?

So I'm stuck here too, I think it's a rare case though.

-- 
Jesse Barnes, Intel Open Source Technology Center