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

Jesse Barnes
2014-10-22T15:42:39Z

On Tue, 21 Oct 2014 16:53:02 +0200
Daniel Vetter <daniel@ffwll.ch> wrote:

> On Thu, Oct 09, 2014 at 12:57:45PM -0700, Jesse Barnes wrote:
> > From: Kristian Høgsberg <hoegsberg@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@gmail.com>
> > Signed-off-by: Jesse Barnes <jbarnes@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.

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

Thanks,
--
Jesse Barnes, Intel Open Source Technology Center