Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933052AbbELMy3 (ORCPT ); Tue, 12 May 2015 08:54:29 -0400 Received: from mail-qk0-f182.google.com ([209.85.220.182]:35679 "EHLO mail-qk0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932882AbbELMy0 (ORCPT ); Tue, 12 May 2015 08:54:26 -0400 From: Paul Moore To: David Airlie , Jani Nikula Cc: intel-gfx@lists.freedesktop.org, Daniel Gultsch , linux-kernel@vger.kernel.org Subject: Re: [Intel-gfx] Commit 0e32b39c ("drm/i915: add DP 1.2 MST support (v0.7)") breaking DP audio on T440s Date: Tue, 12 May 2015 08:54:24 -0400 Message-ID: <2755241.W1jRlsy3sp@sifl> User-Agent: KMail/4.14.6 (Linux/3.16.7-gentoo; KDE/4.14.7; x86_64; ; ) In-Reply-To: <2003013127.14919830.1431331597891.JavaMail.zimbra@redhat.com> References: <877fsf5yqa.fsf@intel.com> <2003013127.14919830.1431331597891.JavaMail.zimbra@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3438 Lines: 71 On Monday, May 11, 2015 04:06:37 AM David Airlie wrote: > ----- Original Message ----- > > From: "Jani Nikula" > > To: "Paul Moore" , "Dave Airlie" > > , intel-gfx@lists.freedesktop.org Cc: "Daniel > > Gultsch" , linux-kernel@vger.kernel.org Sent: Monday, > > 11 May, 2015 6:01:49 PM > > Subject: Re: [Intel-gfx] Commit 0e32b39c ("drm/i915: add DP 1.2 MST > > support (v0.7)") breaking DP audio on T440s> > > On Mon, 11 May 2015, Jani Nikula wrote: > > > On Fri, 08 May 2015, Paul Moore wrote: > > >> 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. > > > > > > Hmm, I never received your first mail. > > > > > > Apparently audio on DP MST is problematic, and the debugging may get a > > > bit involved. Please file a bug at [1] so we don't clutter the lists > > > with logs etc. Please enable drm.debug=14 module parameter and attach > > > (to the bug) dmesg all the way from boot to trying audio on the monitor. > > > > > I started looking at this today, the audio driver needs serious work to > make this happen, I'm trying to investigate how much work that is. Hi Dave, Jani, Thanks for take a look at this, I appreciate it. It looks like the FreeDesktop BZ #89895 is the same problem I'm having so I added my information to that BZ. Let me know if there is anything else I can do to help. * https://bugs.freedesktop.org/show_bug.cgi?id=89895 -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/