Dell displayport YJ3Y6 adapter doesn't drive 4K screen properly
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
mutter (Ubuntu) |
New
|
Undecided
|
Unassigned | ||
xorg-server (Ubuntu) |
New
|
Undecided
|
Unassigned |
Bug Description
I have some early dell 4k 60hz screens - the ones which report 2 panels internally for DP 60Hz - horrid hack I know; I recently got a new XPS laptop and put Ubuntu on it.
That XPS laptop has two USB-C/thunderbolt ports, so to drive the screens I bought two slightly different DP adapters - one with power passthrough, and a cheaper one that only does DP.
The more expensive one 'USB-C to HDMI/DP' drives the monitor happily over DP, though sadly only at 30Hz - can't have everything :/. It reports one monitor as one output: DP-1 in the attached information:
DP-1 connected 3840x2160+0+0 (normal left inverted right x axis y axis) 527mm x 296mm
3840x2160 29.98*+ 30.00 29.97
1920x1200 59.88
...
The cheaper one reports the single monitor as two distinct outputs, at 60hz interestingly -
DP-3-8 connected (normal left inverted right x axis y axis)
1920x2160 59.99 +
DP-3-9 connected 1920x2160+7680+0 (normal left inverted right x axis y axis) 527mm x 296mm
1920x2160 59.99*+
1920x1200 59.88
which in theory if summed together would be one whole screen. But attempting to configure the output results in an error:
xrandr --output DP-1 --auto --left-of eDP-1 --output DP-3-9 --auto --right-of DP-3-8 --output DP-3-8 --auto --right-of eDP-1
xrandr: cannot find crtc for output DP-3-8
I'm not sure if this is an intrinsic limitation of the USB-C->DP dongle, or whether there is something that can be done in the software to deal with this 10 year old hardware hack I have sitting on my desktop.
ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: xorg 1:7.7+19ubuntu14
ProcVersionSign
Uname: Linux 5.4.0-40-generic x86_64
ApportVersion: 2.20.11-0ubuntu27.3
Architecture: amd64
BootLog: Error: [Errno 13] Permission denied: '/var/log/boot.log'
CasperMD5CheckR
CompositorRunning: None
CurrentDesktop: ubuntu:GNOME
Date: Wed Jul 8 11:20:17 2020
DistUpgraded: Fresh install
DistroCodename: focal
DistroVariant: ubuntu
ExtraDebuggingI
GraphicsCard:
Intel Corporation Iris Plus Graphics G7 [8086:8a52] (rev 07) (prog-if 00 [VGA controller])
Subsystem: Dell Iris Plus Graphics G7 [1028:096d]
InstallationDate: Installed on 2020-07-07 (0 days ago)
InstallationMedia: Ubuntu 20.04 LTS "Focal Fossa" - Release amd64 (20200423)
MachineType: Dell Inc. XPS 13 9300
ProcKernelCmdLine: BOOT_IMAGE=
SourcePackage: xorg
Symptom: display
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 05/08/2020
dmi.bios.vendor: Dell Inc.
dmi.bios.version: 1.0.11
dmi.board.name: 0WX9VX
dmi.board.vendor: Dell Inc.
dmi.board.version: A00
dmi.chassis.type: 10
dmi.chassis.vendor: Dell Inc.
dmi.modalias: dmi:bvnDellInc.
dmi.product.family: XPS
dmi.product.name: XPS 13 9300
dmi.product.sku: 096D
dmi.sys.vendor: Dell Inc.
version.compiz: compiz N/A
version.libdrm2: libdrm2 2.4.101-2
version.
version.
version.
version.
version.
version.
version.
Changed in xorg-server (Ubuntu): | |
status: | New → Incomplete |
status: | Incomplete → New |
Changed in mutter (Ubuntu): | |
status: | New → Incomplete |
You certainly seem to have the latest and greatest Intel GPU which should support 4K up to 120Hz:
https:/ /ark.intel. com/content/ www/us/ en/ark/ products/ 196597/ intel-core- i7-1065g7- processor- 8m-cache- up-to-3- 90-ghz. html
So I suspect using "adapters" is the main issue. If you can then please try to get a Thunderbolt- to-DisplayPort CABLE. The Thunderbolt end looks like USB-C but it's much more capable and can carry a full-speed DisplayPort signal.
This is probably not a software bug, or if it is then probably not one we need to worry about if you just get a different cable. In the meantime you might want to try selecting 'Ubuntu on Wayland' from the login screen to see if the experience is any different there.