I have 3 monitors :
- my laptop's screen
- a screen connected to the HDMI port
- a screen connected by HDMI through an USB-C hub.
I sometimes experience graphics corruption inside some application's window, like parts of the window not refreshing, flickering, or showing a part of another app. Sometimes this can be fixed by clicking inside the window or resizing it, sometimes I have to close the app and open it again. This is not limited to any specific application, although it seems to often happen with Geany or CherryTree.
Here is an example with CherryTree after I tried to resize it a few times :
Hardware : Lenovo Thikpad P14s with hybrid graphics (integrated Intel GPU and additional nVidia CPU). I used sudo prime-select intel to set it to use only the integrated GPU, in order to reduce heating and other problems I had when connecting and disconnecting monitors.
Software : Ubuntu 23.04 with KDE Plasma 5.27.4 on Xorg 1.21.1.7
There's nothing in my .xsession-errors or /var/log/Xorg.0.log when this happens.
How should I go about debugging this ? Even though I am an experimented Linux user and system administrator, I don't even know where to begin troubleshooting, and what could be at fault here : the application, plasma, xorg, the video driver...
As far as I know, this never happens when the external monitors are not connected.
Additionnal info : output of sudo inxi -Fxxx, shortened to relevant info :
System:
Host: sylvain-thinkpad Kernel: 6.2.0-20-generic arch: x86_64 bits: 64
compiler: N/A Desktop: KDE Plasma v: 5.27.4 wm: kwin_x11 dm: SDDM
Distro: Ubuntu 23.04 (Lunar Lobster)
Machine:
Type: Laptop System: LENOVO product: 20S40006FR v: ThinkPad P14s Gen 1
Graphics:
Device-1: Intel CometLake-U GT2 [UHD Graphics] vendor: Lenovo driver: i915
v: kernel arch: Gen-9.5 ports: active: DP-3,HDMI-A-2,eDP-1 empty: DP-1,
DP-2, DP-4, HDMI-A-1 bus-ID: 00:02.0 chip-ID: 8086:9b41 class-ID: 0300
Device-2: NVIDIA GP108GLM [Quadro P520] vendor: Lenovo driver: N/A
arch: Pascal pcie: speed: 8 GT/s lanes: 4 bus-ID: 2d:00.0 chip-ID: 10de:1d34
class-ID: 0302
Device-3: Chicony Integrated Camera type: USB driver: uvcvideo
bus-ID: 1-8:4 chip-ID: 04f2:b6d9 class-ID: 0e02 serial: 0001
Display: x11 server: X.Org v: 1.21.1.7 with: Xwayland v: 22.1.8
compositor: kwin_x11 driver: X: loaded: modesetting unloaded: fbdev,vesa
dri: iris gpu: i915 display-ID: :0 screens: 1
Screen-1: 0 s-res: 7040x1440 s-dpi: 96 s-size: 1862x381mm (73.31x15.00")
s-diag: 1901mm (74.83")
Monitor-1: DP-3 mapped: DP-1-1 pos: top-right model: Idek Iiyama PL2791Q
serial: 1153902021080 res: 2560x1440 hz: 60 dpi: 109
size: 597x336mm (23.5x13.23") diag: 686mm (27") modes: max: 2560x1440
min: 640x480
Monitor-2: HDMI-A-2 mapped: HDMI-2 pos: top-center
model: Idek Iiyama PL2791Q serial: 1153902221311 res: 2560x1440 hz: 60
dpi: 109 size: 597x336mm (23.5x13.23") diag: 686mm (27") modes:
max: 2560x1440 min: 640x480
Monitor-3: eDP-1 pos: primary,bottom-l model: AU Optronics 0x403d
res: 1920x1080 hz: 60 dpi: 158 size: 309x174mm (12.17x6.85")
diag: 355mm (14") modes: 1920x1080
API: OpenGL v: 4.6 Mesa 23.0.2 renderer: Mesa Intel UHD Graphics (CML GT2)
direct-render: Yes
