[amdgpu + nvidia PCI passthrough] Screen flickering on ultra wide
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
xorg-server (Ubuntu) |
New
|
Undecided
|
Unassigned | ||
xserver-xorg-video-amdgpu (Ubuntu) |
New
|
Undecided
|
Unassigned |
Bug Description
I'm running 18.04 including all updates on an LG 38WK95C at 3840x1600@75. I'm experiencing constant flickering on screen when setting the refresh rate to 75Hz in settings. When I set to refresh rate to 60Hz, the flicking is gone.
When enabeling freesync in the monitor's settings, the 60Hz isn't available and the only choices are 29.99Hz or 75Hz, which again causes flickering.
This looks like the same issue in bug #1749975.
ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: xorg 1:7.7+19ubuntu7.1
ProcVersionSign
Uname: Linux 4.15.0-43-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.5
Architecture: amd64
BootLog: Error: [Errno 13] Permission denied: '/var/log/boot.log'
CompositorRunning: None
CurrentDesktop: ubuntu:GNOME
Date: Tue Jan 15 16:43:10 2019
DistUpgraded: Fresh install
DistroCodename: bionic
DistroVariant: ubuntu
DkmsStatus:
amdgpu, 18.50-708488, 4.15.0-43-generic, x86_64: installed
nvidia, 415.25, 4.15.0-29-generic, x86_64: installed
nvidia, 415.25, 4.15.0-43-generic, x86_64: installed
ExtraDebuggingI
GraphicsCard:
NVIDIA Corporation Device [10de:1f02] (rev a1) (prog-if 00 [VGA controller])
Subsystem: Micro-Star International Co., Ltd. [MSI] Device [1462:3734]
Advanced Micro Devices, Inc. [AMD/ATI] Polaris12 [1002:699f] (rev c7) (prog-if 00 [VGA controller])
Subsystem: Micro-Star International Co., Ltd. [MSI] Lexa PRO [Radeon RX 550] [1462:8a90]
InstallationDate: Installed on 2019-01-02 (12 days ago)
InstallationMedia: Ubuntu 18.04.1 LTS "Bionic Beaver" - Release amd64 (20180725)
MachineType: To Be Filled By O.E.M. To Be Filled By O.E.M.
ProcKernelCmdLine: BOOT_IMAGE=
SourcePackage: xorg
Symptom: display
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 12/18/2018
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: P1.80
dmi.board.name: B450 Pro4
dmi.board.vendor: ASRock
dmi.chassis.
dmi.chassis.type: 3
dmi.chassis.vendor: To Be Filled By O.E.M.
dmi.chassis.
dmi.modalias: dmi:bvnAmerican
dmi.product.family: To Be Filled By O.E.M.
dmi.product.name: To Be Filled By O.E.M.
dmi.product.
dmi.sys.vendor: To Be Filled By O.E.M.
version.compiz: compiz N/A
version.libdrm2: libdrm2 2.4.91-2
version.
version.
version.
version.
version.
version.
version.
affects: | xorg (Ubuntu) → xorg-server (Ubuntu) |
summary: |
- Screen flickering on ultra wide + [amdgpu + nvidia PCI passthrough] Screen flickering on ultra wide |
tags: | added: amdgpu nvidia radeon |
Changed in xserver-xorg-video-amdgpu (Ubuntu): | |
status: | Expired → New |
Changed in xorg-server (Ubuntu): | |
status: | Expired → New |
According to your XorgLog.txt it looks like the choice of 75Hz is coming from the AMDGPU driver:
[ 97.816] (II) AMDGPU(0): Modeline "3840x1600"x75.0 566.25 3840 4016 4104 4400 1600 1607 1617 1716 +hsync -vsync (128.7 kHz eP)
However the AMDGPU driver is also confused by the monitor's aspect ratio, which might be the problem:
[ 97.816] (WW) AMDGPU(0): Output HDMI-A-0: Strange aspect ratio (879/366), consider adding a quirk
[ 97.816] (WW) AMDGPU(0): Output HDMI-A-0: Strange aspect ratio (879/366), consider adding a quirk
[ 97.816] (WW) AMDGPU(0): Output HDMI-A-0: Strange aspect ratio (879/366), consider adding a quirk
Does the same monitor work when plugged into an Intel or Nvidia GPU?