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

[Daniel Vetter]

On Wed, Oct 22, 2014 at 08:42:32AM -0700, Jesse Barnes wrote:
> On Tue, 21 Oct 2014 16:53:02 +0200
> Daniel Vetter <daniel at ffwll.ch> wrote:
> 
> > On Thu, Oct 09, 2014 at 12:57:45PM -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>
> > 
> > Why exactly does this fail? Is the clock off slightly or are the timings
> > off?
> > 
> > I just wonder whether we should check vrefresh to make sure the bios
> > doesn't sneak a low refresh rate mode past us (from stuck drrs or
> > whatever).
> > 
> > /me thinking a bit paranoid again.
> 
> Yeah you asked this same thing last time.  IIRC it's not a lower clock
> rate like DRRS, but rather different timings.  But Kristian will have
> to post them.

Yeah, I get points for being consistent! And this time around I didn't
even realize it ;-)

> Kristian, can you please post the mode lines from the EDID on this
> machine and the ones the BIOS sets at boot up?

Yeah, I think we should put the full timing data for the bios and edid
mode into the commit message. That way we can later on inspect the
situation again in case of new kinds of brokeness.

Cheers, Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch