From: Jani Nikula <jani.nikula@linux.intel.com>
To: Paul Moore <paul@paul-moore.com>,
Dave Airlie <airlied@redhat.com>,
intel-gfx@lists.freedesktop.org
Cc: Daniel Gultsch <daniel@gultsch.de>, 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: Mon, 11 May 2015 10:59:50 +0300 [thread overview]
Message-ID: <87a8xb5ytl.fsf@intel.com> (raw)
In-Reply-To: <CAHC9VhSztw2ooY=1rt_BOTW+Rd11rynZowsN9qwcH6bxUP10KQ@mail.gmail.com>
On Fri, 08 May 2015, Paul Moore <paul@paul-moore.com> wrote:
> On Fri, Mar 13, 2015 at 11:19 PM, Paul Moore <paul@paul-moore.com> 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
next prev parent reply other threads:[~2015-05-11 7:58 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-14 3:19 Commit 0e32b39c ("drm/i915: add DP 1.2 MST support (v0.7)") breaking DP audio on T440s Paul Moore
2015-05-08 20:45 ` Paul Moore
2015-05-11 7:59 ` Jani Nikula [this message]
2015-05-11 8:01 ` [Intel-gfx] " Jani Nikula
2015-05-11 8:06 ` David Airlie
2015-05-12 12:54 ` Paul Moore
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