From mboxrd@z Thu Jan  1 00:00:00 1970
From: Chris Wilson <chris@chris-wilson.co.uk>
Subject: Re: [PATCH] drm/i915: prefer wide & slow to fast &
	narrow in DP configs
Date: Fri, 22 Jun 2012 18:53:01 +0100
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To: Keith Packard <keithp@keithp.com>, Jesse Barnes <jbarnes@virtuousgeek.org>, intel-gfx@lists.freedesktop.org
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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.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre