Instable DisplayPort with latest radeon driver

[Jan-Marek Glogowski]

I'm using an external monitor on my notebook via DisplayPort => DVI adapter.

After the latest Xenial updates, which included a kernel update to 4.4.0-13.29, I had massive problems, with black screen after reboot to black screen after suspend with the attached monitor.

xrandr still showed the monitor correctly. Additionally I had graphic glitches. Sometimes I managed to re-enable the monitor by detaching it, changing some window in the KDE session and re-attaching it. But it didn't always work. dmesg had some entries like:

[drm:radeon_dp_link_train [radeon]] *ERROR* displayport link status failed

The 12.27 kernel contained a "Pull in upstream AMD code (amdgpu) in Xenial (LP: #1546572)", which also includes "drm/radeon: fix dp link rate selection (v2)" patch

So I took the old radeon modules source from 11.26, compiled and installed it for 13.29, updated the initramfs and my problems are solved.

I didn't yet test the explicit patch. as I don't know where the patchset was taken from.

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: linux-image-4.4.0-13-generic 4.4.0-13.29
ProcVersionSignature: Ubuntu 4.4.0-13.29-generic 4.4.5
Uname: Linux 4.4.0-13-generic x86_64
ApportVersion: 2.20-0ubuntu3
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: jmg 3642 F.... pulseaudio
 /dev/snd/controlC1: jmg 3642 F.... pulseaudio
CurrentDesktop: KDE
Date: Fri Mar 18 12:34:15 2016
HibernationDevice: RESUME=UUID=9e7dddd0-bcd1-4a58-b700-4b47774178d3
MachineType: LENOVO 2550W4R
ProcFB: 0 radeondrmfb
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-4.4.0-13-generic root=/dev/mapper/lenovo--username-root ro splash quiet radeon.dpm=1 nomdmonddf nomdmonisw vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-4.4.0-13-generic N/A
 linux-backports-modules-4.4.0-13-generic N/A
 linux-firmware 1.156
RfKill:
 0: phy0: Wireless LAN
  Soft blocked: no
  Hard blocked: no
SourcePackage: linux
UpgradeStatus: Upgraded to xenial on 2016-03-04 (13 days ago)
dmi.bios.date: 09/21/2010
dmi.bios.vendor: LENOVO
dmi.bios.version: 81ET44WW (1.20 )
dmi.board.name: 2550W4R
dmi.board.vendor: LENOVO
dmi.board.version: Not Available
dmi.chassis.asset.tag: No Asset Information
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: Not Available
dmi.modalias: dmi:bvnLENOVO:bvr81ET44WW(1.20):bd09/21/2010:svnLENOVO:pn2550W4R:pvrThinkPadL512:rvnLENOVO:rn2550W4R:rvrNotAvailable:cvnLENOVO:ct10:cvrNotAvailable:
dmi.product.name: 2550W4R
dmi.product.version: ThinkPad L512
dmi.sys.vendor: LENOVO

[Brad Figg (brad-figg)]

This change was made by a bot.

[Jan-Marek Glogowski (jmglogow)]

The reverted radeon patchset didn't help for long. Actually I don't know why it worked at all, but probably the HW was just breaking down slowly. What finally helped was replacing my DisplayPort to DVI adapter for a new one. This doesn't seem to be a software problem, as the latest kernel works again without a patch.