Comment 0 for bug 1600092

[In comments on 1579481 I mentioned that I had found and cherry-picked a fix from upstream. I was asked to file another bug so that my hardware information could be compared. apport will show kernel version 4.4.0-24 but the issue is reproducible on 4.4.0-28 as well-- just didn't want to uninstall my fixed version in order to post my hardware info.]

I have an AMD based desktop system with onboard/APU graphics. I have a monitor which had been hooked up via DVI until yesterday. Picked up a nice refurbished monitor which I plugged in to the onboard DVI port, and moved the other monitor to the VGA port. Ubuntu recognizes it but it does not show anything. Monitor works fine during initial boot/BIOS.

dmesg says:

[ 3.311243] [drm] Initialized radeon 2.43.0 20080528 for 0000:00:01.0 on minor 0
[ 16.843630] [drm:radeon_dp_link_train [radeon]] *ERROR* clock recovery reached max voltage
[ 16.843663] [drm:radeon_dp_link_train [radeon]] *ERROR* clock recovery failed

Searching for those errors I found bug 1579481 which says it is fixed upstream, so I went searching for which commit might have fixed it, and I found this one: https://github.com/torvalds/linux/commit/c8213a638f65bf487c10593c216525952cca3690

I built a packaged kernel from xenial git source plus that one commit, and when I boot that kernel, the monitor in the VGA port works fine. Probably worth adding that commit to the official Xenial kernel since others stated that the issue is a regression.

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: linux-image-4.4.0-24-generic 4.4.0-24.43
ProcVersionSignature: Ubuntu 4.4.0-24.43-generic 4.4.10
Uname: Linux 4.4.0-24-generic x86_64
ApportVersion: 2.20.1-0ubuntu2.1
Architecture: amd64
AudioDevicesInUse: Error: command ['fuser', '-v', '/dev/dsp1', '/dev/snd/by-path', '/dev/snd/hwC1D0', '/dev/snd/pcmC1D2c', '/dev/snd/pcmC1D1p', '/dev/snd/pcmC1D0c', '/dev/snd/pcmC1D0p', '/dev/snd/controlC1', '/dev/snd/hwC0D0', '/dev/snd/pcmC0D3p', '/dev/snd/controlC0', '/dev/snd/seq', '/dev/snd/timer'] failed with exit code 1:
CurrentDesktop: Unity
Date: Thu Jul 7 23:39:27 2016
HibernationDevice: RESUME=UUID=5012a75e-a79a-46fa-94f7-db367d25b3f0
InstallationDate: Installed on 2011-11-01 (1710 days ago)
InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Release amd64 (20111012)
MachineType: Gigabyte Technology Co., Ltd. To be filled by O.E.M.
ProcFB: 0 radeondrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.4.0-24-generic root=UUID=d13d1157-b660-43bb-a0af-fa8771808d10 ro quiet splash vt.handoff=7
PulseList: Error: command ['pacmd', 'list'] failed with exit code 1: No PulseAudio daemon running, or not running as session daemon.
RelatedPackageVersions:
 linux-restricted-modules-4.4.0-24-generic N/A
 linux-backports-modules-4.4.0-24-generic N/A
 linux-firmware 1.157.1
RfKill:

SourcePackage: linux
UpgradeStatus: Upgraded to xenial on 2016-07-04 (4 days ago)
dmi.bios.date: 05/28/2014
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: F5
dmi.board.asset.tag: To be filled by O.E.M.
dmi.board.name: F2A88X-D3H
dmi.board.vendor: Gigabyte Technology Co., Ltd.
dmi.board.version: x.x
dmi.chassis.asset.tag: To Be Filled By O.E.M.
dmi.chassis.type: 3
dmi.chassis.vendor: Gigabyte Technology Co., Ltd.
dmi.chassis.version: To Be Filled By O.E.M.
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvrF5:bd05/28/2014:svnGigabyteTechnologyCo.,Ltd.:pnTobefilledbyO.E.M.:pvrTobefilledbyO.E.M.:rvnGigabyteTechnologyCo.,Ltd.:rnF2A88X-D3H:rvrx.x:cvnGigabyteTechnologyCo.,Ltd.:ct3:cvrToBeFilledByO.E.M.:
dmi.product.name: To be filled by O.E.M.
dmi.product.version: To be filled by O.E.M.
dmi.sys.vendor: Gigabyte Technology Co., Ltd.