Bug 107835

Summary: DisplayPort audio stopped working in a kernel upgrade
Product: DRI Reporter: Ben Morris <bugs>
Component: DRM/AMDgpuAssignee: Default DRI bug account <dri-devel>
Status: RESOLVED MOVED QA Contact:
Severity: normal    
Priority: medium CC: harry.wentland, nicholas.kazlauskas, sunpeng.li
Version: unspecified   
Hardware: Other   
OS: All   
Whiteboard:
i915 platform: i915 features:

Description Ben Morris 2018-09-05 10:29:44 UTC 
In a recent kernel upgrade, my DisplayPort audio output stopped working. PulseAudio showed no available profiles for the device, while aplay appeared to work normally but produced no sound. I'm running Debian Unstable, and I have a Radeon RX 470.

I have bisected (in linux-stable), and narrowed down the start of the problem to this commit:

commit 9168c089a2122606e2c01f6fbeda85ff950ac189 (HEAD, refs/bisect/bad)
Author: Alex Deucher <alexander.deucher@amd.com>
Date:   Tue Jul 10 12:56:45 2018 -0500

    Revert "drm/amd/display: Don't return ddc result and read_bytes in same return value"
    
    commit 5292221d6ddfed75e5b46cd42237a677094b99f3 upstream.
    
    This reverts commit 018d82e5f02ef3583411bcaa4e00c69786f46f19.
    
    This breaks DDC in certain cases.  Revert for 4.18 and previous kernels.
    For 4.19, this is fixed with the following more extensive patches:
    drm/amd/display: Serialize is_dp_sink_present
    drm/amd/display: Break out function to simply read aux reply
    drm/amd/display: Return aux replies directly to DRM
    drm/amd/display: Right shift AUX reply value sooner than later
    drm/amd/display: Read AUX channel even if only status byte is returned
    
    Link: https://lists.freedesktop.org/archives/amd-gfx/2018-July/023788.html
    Acked-by: Harry Wentland <harry.wentland@amd.com>
    Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
    Cc: stable@vger.kernel.org
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>


I have tried kernel 4.19-rc2, and, as suggested in the commit message, the audio problem does indeed seem to be resolved in 4.19.

I have never seen the stacktrace associated with the same commit at https://bugzilla.kernel.org/show_bug.cgi?id=200667
Comment 1 Marti Raudsepp 2019-08-26 19:03:43 UTC 
Graphics card: ASUS Radeon R9 270
Kernel: 5.2.9-arch1-1-ARCH

I recently had some issues with the "radeon" driver and discovered that the "amdgpu" driver now has support for Southern Islands (SI) GPUs using the amdgpu.si_support=1 boot flag.

Graphics stuff works great with "amdgpu" so far, however, all HDMI audio outputs are marked as "(unplugged) (unavailable)". This seems to be a similar problem, based on IRC logs by BCMM at https://dri.freedesktop.org/~cbrill/dri-log/?channel=radeon&highlight_names=&date=2018-09-05
which lead me to this bug report.
His screenshot from pavuctl: https://i.imgur.com/67HYPG3.png

Ben, are you still having this issue too?
Comment 2 Alex Deucher 2019-08-26 19:09:42 UTC 
Southern Islands is not supported by the DC modesetting code, so this is not the same issue as the OP's.
Comment 3 Marti Raudsepp 2019-08-26 20:11:42 UTC 
Thanks Alex, reported new bug 111492.
Comment 4 Martin Peres 2019-11-19 08:54:20 UTC 
-- GitLab Migration Automatic Message --

This bug has been migrated to freedesktop.org's GitLab instance and has been closed from further activity.

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