From mboxrd@z Thu Jan 1 00:00:00 1970 From: Adam Jackson Subject: Re: [Intel-gfx] [PATCH 3/7] drm/i915: Treat PCH eDP like DP in most places Date: Wed, 02 Nov 2011 15:36:20 -0400 Message-ID: <4EB19BB4.6030505@redhat.com> References: <1320214830-12696-1-git-send-email-keithp@keithp.com> <1320214830-12696-4-git-send-email-keithp@keithp.com> <20111102092019.3a635632@jbarnes-desktop> <4EB17A50.6050804@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Keith Packard Cc: Jesse Barnes , intel-gfx@lists.freedesktop.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org List-Id: intel-gfx@lists.freedesktop.org On 11/2/11 1:31 PM, Keith Packard wrote: > On Wed, 02 Nov 2011 13:13:52 -0400, Adam Jackson wrote: > >> Given the choice of trusting DPCD or the VBT, I'd definitely prefer >> DPCD. > > Except that the DPCD is coded into the monitor while the VBT is done by > the platform. And, it's the platform which may neglect to connect some > of the wires. My reasoning about this has been: The maximum link configuration in DPCD is going to fit - and minimally fit - the maximum supported configuration (depth/rate/size/etc), because otherwise the hardware would have been more expensive to produce. The VBT is going to be crap. But as always, "do what the Windows driver does" seems like a good strategy. Do we know? > Any bets on how long until we find a machine that has right value in the > VBT and the wrong one in DPCD? Or a machine with wrong values in both places? I will happily pay $20 to the first person to find a monitor with broken link/lane in DPCD, on the understanding that they take it (the $20) to the nearest hardware store, buy a hammer, and smash the monitor. Preferably with the video uploaded to youtube. - ajax