From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chris Wilson Subject: Re: [PATCH] drm/i915/dp: Fix I2C/EDID handling with active DisplayPort to DVI converter Date: Wed, 08 Dec 2010 20:17:12 +0000 Message-ID: <849307$amb8jq@azsmga001.ch.intel.com> References: <20101208161021.GF20844@rd.bbc.co.uk> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20101208161021.GF20844@rd.bbc.co.uk> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dri-devel-bounces+sf-dri-devel=m.gmane.org@lists.freedesktop.org Errors-To: dri-devel-bounces+sf-dri-devel=m.gmane.org@lists.freedesktop.org To: David Flynn , dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org List-Id: intel-gfx@lists.freedesktop.org On Wed, 8 Dec 2010 16:10:21 +0000, David Flynn wrote: > The DisplayPort standard (1.1a) states that: > The I2C-over-AUX Reply field is valid only when Native AUX CH Reply > field is AUX_ACK (00). When Native AUX CH Reply field is not 00, then, > I2C-over-AUX Reply field must be 00 and be ignored. > > This fixes broken EDID reading when using an active DisplayPort to > duallink DVI converter. If the AUX CH replier chooses to defer the > transaction, a short read occurs and erroneous data is returned as > the i2c reply due to a lack of length checking and failure to check > for AUX ACK. And it didn't break my bog standard DP setup. :) Applied to -fixes and tagged for stable. Thanks, -Chris -- Chris Wilson, Intel Open Source Technology Centre