I forgot a display signal doesn't include any alpha channel, so yeah 8 bpc will require less bandwidth than 10 bpc.
The maximum capability of the monitor should be advertised in its EDID. At least modern monitors do. You can check it using the 'edid-decode' command and grepping for 'bits per primary'. What gets returned? Can you share the EDID of the troublesome display? -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to xorg-server in Ubuntu. https://bugs.launchpad.net/bugs/1890772 Title: Some external 4K monitor is not working properly Status in OEM Priority Project: Incomplete Status in xorg-server package in Ubuntu: Incomplete Bug description: The bug is originated from, https://bugs.launchpad.net/somerville/+bug/1887915/ https://bugs.launchpad.net/somerville/+bug/1886778 It has some problem when user connect to external 4K monitor with refresh rate 60. The problem can be solved by lower the bpc, or lower the refresh rate. `xrandr --output DP-3 --set "max bpc" 8` Would like to open this bug to open discussion for enhancing user experience. --- ProblemType: Bug ApportVersion: 2.20.11-0ubuntu27.4 Architecture: amd64 BootLog: Error: [Errno 13] Permission denied: '/var/log/boot.log' CasperMD5CheckResult: skip CompositorRunning: None CurrentDesktop: ubuntu:GNOME DistUpgraded: Fresh install DistributionChannelDescriptor: # This is the distribution channel descriptor for the OEM CDs # For more information see http://wiki.ubuntu.com/DistributionChannelDescriptor canonical-oem-somerville-focal-amd64-20200502-85+fossa-samwell-tgl+X42 DistroCodename: focal DistroRelease: Ubuntu 20.04 DistroVariant: ubuntu DkmsStatus: nvidia, 440.100, 5.6.0-1021-oem, x86_64: installed ExtraDebuggingInterest: Yes GraphicsCard: Intel Corporation Device [8086:9a49] (rev 01) (prog-if 00 [VGA controller]) Subsystem: Dell Device [1028:09fc] Subsystem: Dell GP107M [GeForce MX350] [1028:09fc] InstallationDate: Installed on 2020-08-07 (0 days ago) InstallationMedia: Ubuntu 20.04 "Focal" - Build amd64 LIVE Binary 20200502-05:58 Package: xorg 1:7.7+19ubuntu14 [origin: unknown] PackageArchitecture: amd64 ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-5.6.0-1021-oem root=UUID=41be2253-410a-4ef7-a096-4193a58efdbd ro quiet splash vt.handoff=7 ProcVersionSignature: Ubuntu 5.6.0-1021.21-oem 5.6.19 Tags: third-party-packages focal ubuntu Uname: Linux 5.6.0-1021-oem x86_64 UnreportableReason: This is not an official Ubuntu package. Please remove any third party package and try again. UpgradeStatus: No upgrade log present (probably fresh install) UserGroups: adm cdrom dip lpadmin plugdev sambashare sudo _MarkForUpload: True version.compiz: compiz N/A version.libdrm2: libdrm2 2.4.101-2 version.libgl1-mesa-dri: libgl1-mesa-dri 20.0.8-0ubuntu1~20.04.1 version.libgl1-mesa-glx: libgl1-mesa-glx N/A version.xserver-xorg-core: xserver-xorg-core 2:1.20.8-2ubuntu2.2 version.xserver-xorg-input-evdev: xserver-xorg-input-evdev N/A version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:19.1.0-1 version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.917+git20200226-1 version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.16-1 To manage notifications about this bug go to: https://bugs.launchpad.net/oem-priority/+bug/1890772/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp
