Re: [PATCH] drm/i915: prefer wide & slow to fast & narrow in DP configs

[Daniel Vetter <daniel@ffwll.ch>]

On Fri, Jun 22, 2012 at 06:53:01PM +0100, Chris Wilson wrote:
> On Fri, 22 Jun 2012 10:40:22 -0700, Keith Packard <keithp@keithp.com> wrote:
> > Chris Wilson <chris@chris-wilson.co.uk> writes:
> > 
> > > On Thu, 21 Jun 2012 18:13:19 -0700, Keith Packard <keithp@keithp.com> wrote:
> > 
> > > It was structured to minimise lane count because certain chipsets did
> > > not wire up all the lanes, right? Is that still relevant as we are using
> > > the advertised max_lane_count from the DPCD now?
> > 
> > We've always used the max_lane_count from dpcd; has there been some
> > recent change that fixed usage of that? What I recall is one acer laptop
> > that advertised 4 lanes but had only wired up two of them.
> 
> The only recentish change was your
> 
> commit 9a10f401a401ca69c6537641c8fc0d6b57b5aee8
> Author: Keith Packard <keithp@keithp.com>
> Date:   Wed Nov 2 13:03:47 2011 -0700
> 
>     drm/i915: Use DPCD value for max DP lanes.
> 
>     The BIOS VBT value for an eDP panel has been shown to be incorrect on
>     one machine, and we haven't found any machines where the DPCD value
>     was wrong, so we'll use the DPCD value everywhere.
> 
> We can but hope that no manufacturer lies in the DPCD.

Ok, I've merged this patch because it fixes a regression and this commit
Chris has dug out seems to indicate that we won't hit any known issues on
eDP panels. I guess if it blows up again, we'll have to take another look.
-Daniel
-- 
Daniel Vetter
Mail: daniel@ffwll.ch
Mobile: +41 (0)79 365 57 48