Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932183AbbEHUpk (ORCPT ); Fri, 8 May 2015 16:45:40 -0400 Received: from mail-ob0-f171.google.com ([209.85.214.171]:33480 "EHLO mail-ob0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753668AbbEHUpg (ORCPT ); Fri, 8 May 2015 16:45:36 -0400 MIME-Version: 1.0 X-Originating-IP: [76.119.162.148] In-Reply-To: References: Date: Fri, 8 May 2015 16:45:36 -0400 Message-ID: Subject: Re: Commit 0e32b39c ("drm/i915: add DP 1.2 MST support (v0.7)") breaking DP audio on T440s From: Paul Moore To: Dave Airlie , intel-gfx@lists.freedesktop.org Cc: linux-kernel@vger.kernel.org, Daniel Gultsch Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1830 Lines: 40 On Fri, Mar 13, 2015 at 11:19 PM, Paul Moore wrote: > Ever since v3.17 I've had a problem with displayport audio on my > system, but until lately I haven't had a chance to bisect the problem. > After a few rounds I've isolated the buggy commit to 0e32b39c > ("drm/i915: add DP 1.2 MST support (v0.7)"). > > Simply put, prior to v3.17 everything worked correctly: audio from my > system was routed to my monitor via the DP connection and finally out > to the speakers connected to the monitor. However, starting with > kernel v3.17 this no longer works. The various PulseAudio tools all > indicate that the HDMI/DP audio output is unplugged/not-available. > I've tried a few different xrandr commands found via google and > manpages but nothing short of reverting to v3.16 solves the problem. > I'm hoping that someone with more understanding of the Intel graphics > drivers will be able to make some sense of it all and provide a fix. > I'm more than happy to provide additional information and test any > patches you may have. > > For reference, my system is a ThinkPad T440s with a "Intel Corporation > Haswell-ULT Integrated Graphics Controller (rev 0b)" (according to > lspci) connected to a Dell U3011 via a Gefen DP KVM. Help? The problem still exists on v4.0.1 and I know of at least one other person that has reported the same problem. As I said above, I'm willing to do any additional debugging/testing needed, I just could use some help on resolving this as I am definitely not a X/graphics-driver expert. -Paul -- paul moore www.paul-moore.com -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/