Bug 102401

Summary: Radeon Displayport Audio Warping
Product: Drivers Reporter: Maxqia (public)
Component: Video(DRI - non Intel)Assignee: drivers_video-dri
Status: REOPENED ---    
Severity: normal CC: alexdeucher, public, szg0000, vitor.hda
Priority: P1    
Hardware: All   
OS: Linux   
Kernel Version: 4.2 RC5 Tree: Mainline
Regression: No
Attachments: Patch
dmesg log
Possible Patch
Updated Patch
Explained Patch

Description Maxqia 2015-08-07 01:05:55 UTC
I'm having issues with Linux 4.2 RC5 with the Displayport audio being deeper then normal. Doesn't seem to happen with 4.1.3 with a backported patch from https://bugzilla.kernel.org/attachment.cgi?id=183611
Comment 1 Maxqia 2015-08-10 21:09:47 UTC
Created attachment 184611 [details]
Patch

Reverting Commit 7726e72b3d6879ee5fc743a230eb6f5afa12844b Seems to fix my issues.
Comment 2 Alex Deucher 2015-08-10 21:17:19 UTC
Are you sure that's the right commit?  That commit shouldn't have any affect on DP audio.  All it does is move the check for monitor audio support from radeon_atom_encoder_mode_set() into radeon_audio_mode_set().  It doesn't change the hw programming at all.
Comment 3 Maxqia 2015-08-10 22:47:03 UTC
Yes, I just double checked. With the commit, the displayport audio is warped.
Comment 4 Maxqia 2015-08-11 03:28:10 UTC
Huh seems to be the EDID detection. Windows/xrandr --verbose seem to get the EDID right but get-edid doesn't.
Comment 5 Maxqia 2015-08-17 08:47:19 UTC
Replacing drm_detect_monitor_audio(radeon_connector_edid(connector)) with true seems to fix the problem.
Comment 6 Alex Deucher 2015-08-19 18:00:42 UTC
(In reply to Maxqia from comment #5)
> Replacing drm_detect_monitor_audio(radeon_connector_edid(connector)) with
> true seems to fix the problem.

This means the EDID from your monitor claims not to support audio.
Comment 7 Maxqia 2015-08-20 01:33:04 UTC
Created attachment 185301 [details]
dmesg log
Comment 8 Maxqia 2015-08-20 01:34:46 UTC
It works with fglrx, also in the dmesg log it says "[drm:drm_detect_monitor_audio] Monitor has basic audio support"
Which is when it should output true
Comment 9 Maxqia 2015-08-21 00:28:13 UTC
Created attachment 185391 [details]
Possible Patch
Comment 10 Maxqia 2015-08-21 23:44:40 UTC
Created attachment 185441 [details]
Updated Patch
Comment 11 Maxqia 2015-09-17 03:23:43 UTC
Any Updates?
Comment 12 Alex Deucher 2015-09-23 15:42:05 UTC
I don't see what this patch changes.
Comment 13 Maxqia 2016-09-18 02:43:17 UTC
Looking back with an extra year of programming knowledge, it seems like commit 7726e72b3d6879ee5fc743a230eb6f5afa12844b doesn't do anything except add a drm_detect_monitor_audio to the hdmi audio pathway ..., before that commit only Displayport was checked for audio. Anyways, issue still present.
Comment 14 Maxqia 2016-09-18 03:47:35 UTC
Created attachment 238501 [details]
Explained Patch
Comment 15 Maxqia 2017-03-04 07:40:11 UTC
Comment on attachment 238501 [details]
Explained Patch

:/ I really don't know what I'm doing...
Commenting this if block fixes it...
https://github.com/torvalds/linux/blob/9439b3710df688d853eb6cb4851256f2c92b1797/drivers/gpu/drm/radeon/radeon_atombios.c#L1267
That probably means that the thing setting the display clock frequency is broken in some way...
Comment 16 Vitor Antunes 2018-10-10 22:33:39 UTC
I'm having the same problem with my Tahiti GPU.
This output seems to confirm that there's an EDID issue:
> tail -n+1 /proc/asound/card*/eld*
[...]
edid_version		[0x0] no CEA EDID Timing Extension block present
[...]

These patches touch DCE6 and such: https://lists.freedesktop.org/archives/amd-gfx/2018-October/027462.html
Maybe it fixes this issue?

Don't have the availability to test at the moment.