Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752426AbbEKH60 (ORCPT ); Mon, 11 May 2015 03:58:26 -0400 Received: from mga11.intel.com ([192.55.52.93]:49540 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751058AbbEKH6Z (ORCPT ); Mon, 11 May 2015 03:58:25 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.13,405,1427785200"; d="scan'208";a="723862298" From: Jani Nikula To: Paul Moore , Dave Airlie , intel-gfx@lists.freedesktop.org Cc: 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 In-Reply-To: Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo References: User-Agent: Notmuch/0.19+112~g77230b0 (http://notmuchmail.org) Emacs/24.4.1 (x86_64-pc-linux-gnu) Date: Mon, 11 May 2015 10:59:50 +0300 Message-ID: <87a8xb5ytl.fsf@intel.com> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2495 Lines: 60 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. BR, Jani. > > -Paul > > -- > paul moore > www.paul-moore.com > _______________________________________________ > Intel-gfx mailing list > Intel-gfx@lists.freedesktop.org > http://lists.freedesktop.org/mailman/listinfo/intel-gfx -- Jani Nikula, Intel Open Source Technology Center -- 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/