graphics glitches after disconnecting from external displays

[taguely]

I've been experiencing a fairly repeatable graphics glitch on two different Lenovo ThinkPad laptops (an E14 and an X230) running the the latest version of Mint Cinnamon with very little customization. For context, my normal use is to switch a laptop between a USB dock in my office, a USB dock at home, external displays in meeting rooms (HDMI or USB-C), and classrooms (HDMI or USB-C).

Issue: very obvious graphics glitching (usually burst of horizontal lines) that seems to blend together aspects of the login screen with aspects of the desktop, at times showing some application content without logging in.

When it happens: any time I switch between any of my external display setups, the first time I open the laptop, there is some amount of graphics glitching. It sometimes is minimal and can still allow me to use the machine, but sometimes it makes the system unusable.

"Fixes": since it usually only happens the first time i open the laptop, i often open the laptop, then close it again, then open it and continue. something about the extra suspend cycle seems to help. when that doesn't work, if i can, i open the display settings, change something like the resolution, accept the new setting, change it back, accept the new setting, and continue. this also seems to help, at least sometimes.

Note: I have noticed on at least one occasion that the system's display settings included a 60" display when it was connected to a 24" display, so there is definitely some stale state somewhere in the system, and I believe this at least heading in the direction of the root cause of the issue.

[SMG]

I've been experiencing a fairly repeatable graphics glitch on two different Lenovo ThinkPad laptops (an E14 and an X230) running the the latest version of Mint Cinnamon with very little customization. For context, my normal use is to switch a laptop between a USB dock in my office, a USB dock at home, external displays in meeting rooms (HDMI or USB-C), and classrooms (HDMI or USB-C).

Welcome to the forum, taguely.

These types of issues are often related to hardware so we need to know more than just the model name. Please open the System Reports app and click the System Information tab on the left. Your computer's information should come up in the right pane. Then click the Copy button in the lower right and paste the results into a reply window here so we can see how Linux Mint views your hardware.

Note: I have noticed on at least one occasion that the system's display settings included a 60" display when it was connected to a 24" display, so there is definitely some stale state somewhere in the system, and I believe this at least heading in the direction of the root cause of the issue.

Linux-based distros have hot-plug capability. Rather than there being "stale" information, it is more likely incorrect monitor information is in the monitor. The manufacturer database is not always properly updated.

[taguely]

System information:

Code: Select all

System:
  Kernel: 5.15.0-101-generic x86_64 bits: 64 compiler: gcc v: 11.4.0 Desktop: Cinnamon 6.0.4
    tk: GTK 3.24.33 wm: muffin vt: 7 dm: LightDM 1.30.0 Distro: Linux Mint 21.3 Virginia
    base: Ubuntu 22.04 jammy
Machine:
  Type: Laptop System: LENOVO product: 20RA004YUS v: ThinkPad E14 serial: <superuser required>
    Chassis: type: 10 serial: <superuser required>
  Mobo: LENOVO model: 20RA004YUS v: SDK0J40697 WIN serial: <superuser required> UEFI: LENOVO
    v: R16ET40W (1.26 ) date: 11/23/2023
Battery:
  ID-1: BAT0 charge: 35.8 Wh (86.7%) condition: 41.3/45.7 Wh (90.2%) volts: 12.4 min: 11.1
    model: SMP 5B10W138 type: Li-poly serial: <filter> status: Charging cycles: 164
  Device-1: hidpp_battery_2 model: Logitech Wireless Mouse M510 serial: <filter>
    charge: 55% (should be ignored) rechargeable: yes status: Discharging
  Device-2: hidpp_battery_3 model: Logitech K350 serial: <filter>
    charge: 70% (should be ignored) rechargeable: yes status: Discharging
CPU:
  Info: quad core model: Intel Core i5-10210U bits: 64 type: MT MCP smt: enabled
    arch: Comet/Whiskey Lake note: check rev: C cache: L1: 256 KiB L2: 1024 KiB L3: 6 MiB
  Speed (MHz): avg: 2300 min/max: 400/4200 cores: 1: 2300 2: 2300 3: 2300 4: 2300 5: 2300
    6: 2300 7: 2300 8: 2300 bogomips: 33599
  Flags: avx avx2 ht lm nx pae sse sse2 sse3 sse4_1 sse4_2 ssse3 vmx
Graphics:
  Device-1: Intel CometLake-U GT2 [UHD Graphics] vendor: Lenovo driver: i915 v: kernel ports:
    active: DP-2,DP-6 off: eDP-1 empty: DP-1, DP-5, HDMI-A-1, HDMI-A-2 bus-ID: 00:02.0
    chip-ID: 8086:9b41 class-ID: 0300
  Device-2: Chicony ASUS USB2.0 Webcam type: USB driver: uvcvideo bus-ID: 1-2.3.4:15
    chip-ID: 04f2:b1f2 class-ID: 0e02
  Device-3: IMC Networks Integrated Camera type: USB driver: uvcvideo bus-ID: 1-8:3
    chip-ID: 13d3:5415 class-ID: 0e02
  Display: x11 server: X.Org v: 1.21.1.4 driver: X: loaded: modesetting unloaded: fbdev,vesa
    gpu: i915 display-ID: :0 screens: 1
  Screen-1: 0 s-res: 3840x1080 s-dpi: 96 s-size: 1016x286mm (40.0x11.3") s-diag: 1055mm (41.6")
  Monitor-1: DP-1-1 mapped: DP-2 pos: primary,left model: Asus VK278 serial: <filter>
    res: 1920x1080 hz: 60 dpi: 82 size: 598x336mm (23.5x13.2") diag: 686mm (27") modes:
    max: 1920x1080 min: 720x400
  Monitor-2: DP-1-3 pos: right res: 1920x1080 hz: 60 dpi: 79 size: 621x341mm (24.4x13.4")
    diag: 708mm (27.9")
  OpenGL: renderer: Mesa Intel UHD Graphics (CML GT2) v: 4.6 Mesa 23.2.1-1ubuntu3.1~22.04.2
    direct render: Yes
Audio:
  Device-1: Intel Comet Lake PCH-LP cAVS vendor: Lenovo driver: snd_hda_intel v: kernel
    bus-ID: 00:1f.3 chip-ID: 8086:02c8 class-ID: 0403
  Device-2: Lenovo ThinkPad USB-C Dock Gen2 USB Audio type: USB
    driver: hid-generic,snd-usb-audio,usbhid bus-ID: 1-2.3.3.2:17 chip-ID: 17ef:a396 class-ID: 0300
    serial: <filter>
  Device-3: C-Media Blue Snowball type: USB driver: hid-generic,snd-usb-audio,usbhid
    bus-ID: 1-2.3.3.3:18 chip-ID: 0d8c:0005 class-ID: 0300 serial: <filter>
  Sound Server-1: ALSA v: k5.15.0-101-generic running: yes
  Sound Server-2: PulseAudio v: 15.99.1 running: yes
  Sound Server-3: PipeWire v: 0.3.48 running: yes
Network:
  Device-1: Realtek RTL8111/8168/8411 PCI Express Gigabit Ethernet vendor: Lenovo driver: r8169
    v: kernel pcie: speed: 2.5 GT/s lanes: 1 port: 3000 bus-ID: 04:00.0 chip-ID: 10ec:8168
    class-ID: 0200
  IF: enp4s0 state: down mac: <filter>
  Device-2: Realtek RTL8822CE 802.11ac PCIe Wireless Network Adapter vendor: Lenovo
    driver: rtw_8822ce v: N/A pcie: speed: 2.5 GT/s lanes: 1 port: 2000 bus-ID: 05:00.0
    chip-ID: 10ec:c822 class-ID: 0280
  IF: wlp5s0 state: up mac: <filter>
  Device-3: Lenovo USB-C Dock Ethernet type: USB driver: r8152 bus-ID: 2-2.1:6
    chip-ID: 17ef:a387 class-ID: 0000 serial: <filter>
  IF: enx5cff35d8d8c1 state: up speed: 100 Mbps duplex: full mac: <filter>
  IF-ID-1: mpqemubr0 state: down mac: <filter>
  IF-ID-2: virbr0 state: up speed: 10 Mbps duplex: unknown mac: <filter>
  IF-ID-3: vnet0 state: unknown speed: 10 Mbps duplex: full mac: <filter>
Drives:
  Local Storage: total: 238.47 GiB used: 199.37 GiB (83.6%)
  ID-1: /dev/sda vendor: SanDisk model: SD8SN8U-256G-1006 size: 238.47 GiB speed: 6.0 Gb/s
    type: SSD serial: <filter> rev: 0006 scheme: GPT
Partition:
  ID-1: / size: 233.18 GiB used: 199.36 GiB (85.5%) fs: ext4 dev: /dev/sda2
  ID-2: /boot/efi size: 511 MiB used: 6.1 MiB (1.2%) fs: vfat dev: /dev/sda1
Swap:
  ID-1: swap-1 type: file size: 2 GiB used: 381.9 MiB (18.6%) priority: -2 file: /swapfile
USB:
  Hub-1: 1-0:1 info: Hi-speed hub with single TT ports: 12 rev: 2.0 speed: 480 Mb/s
    chip-ID: 1d6b:0002 class-ID: 0900
  Hub-2: 1-2:12 info: Lenovo USB2.0 Hub ports: 4 rev: 2.1 speed: 480 Mb/s chip-ID: 17ef:a392
    class-ID: 0900
  Hub-3: 1-2.3:13 info: Lenovo USB2.0 Hub ports: 4 rev: 2.1 speed: 480 Mb/s chip-ID: 17ef:a394
    class-ID: 0900
  Hub-4: 1-2.3.3:14 info: Lenovo USB2.0 Hub ports: 4 rev: 2.0 speed: 480 Mb/s power: 100mA
    chip-ID: 17ef:a395 class-ID: 0900
  Device-1: 1-2.3.3.1:22 info: Cypress USB-I2C Bridge type: <vendor specific> driver: N/A
    interfaces: 2 rev: 2.0 speed: 12 Mb/s power: 100mA chip-ID: 04b4:521a class-ID: 0000
  Device-2: 1-2.3.3.2:17 info: Lenovo ThinkPad USB-C Dock Gen2 USB Audio type: Audio,HID
    driver: hid-generic,snd-usb-audio,usbhid interfaces: 4 rev: 2.0 speed: 12 Mb/s power: 100mA
    chip-ID: 17ef:a396 class-ID: 0300 serial: <filter>
  Device-3: 1-2.3.3.3:18 info: C-Media Blue Snowball type: Audio,HID
    driver: hid-generic,snd-usb-audio,usbhid interfaces: 3 rev: 1.1 speed: 12 Mb/s power: 100mA
    chip-ID: 0d8c:0005 class-ID: 0300 serial: <filter>
  Device-4: 1-2.3.3.4:19 info: Logitech Unifying Receiver type: Keyboard,Mouse,HID
    driver: logitech-djreceiver,usbhid interfaces: 3 rev: 2.0 speed: 12 Mb/s power: 98mA
    chip-ID: 046d:c52b class-ID: 0300
  Device-5: 1-2.3.4:15 info: Chicony ASUS USB2.0 Webcam type: Video driver: uvcvideo
    interfaces: 2 rev: 2.0 speed: 480 Mb/s power: 500mA chip-ID: 04f2:b1f2 class-ID: 0e02
  Device-6: 1-8:3 info: IMC Networks Integrated Camera type: Video driver: uvcvideo
    interfaces: 2 rev: 2.0 speed: 480 Mb/s power: 500mA chip-ID: 13d3:5415 class-ID: 0e02
  Hub-5: 2-0:1 info: Super-speed hub ports: 6 rev: 3.1 speed: 10 Gb/s chip-ID: 1d6b:0003
    class-ID: 0900
  Hub-6: 2-2:5 info: Lenovo USB3.1 Hub ports: 4 rev: 3.1 speed: 5 Gb/s chip-ID: 17ef:a391
    class-ID: 0900
  Device-1: 2-2.1:6 info: Lenovo USB-C Dock Ethernet type: Network driver: r8152 interfaces: 1
    rev: 3.0 speed: 5 Gb/s power: 288mA chip-ID: 17ef:a387 class-ID: 0000 serial: <filter>
  Hub-7: 2-2.3:7 info: Lenovo USB3.1 Hub ports: 4 rev: 3.1 speed: 5 Gb/s chip-ID: 17ef:a393
    class-ID: 0900
Sensors:
  System Temperatures: cpu: 44.0 C pch: 38.0 C mobo: N/A
  Fan Speeds (RPM): N/A
Repos:
  Packages: 2350 apt: 2339 snap: 11
  No active apt repos in: /etc/apt/sources.list
  Active apt repos in: /etc/apt/sources.list.d/obsproject-obs-studio-jammy.list
    1: deb [signed-by=/etc/apt/keyrings/obsproject-obs-studio-jammy.gpg] https: //ppa.launchpadcontent.net/obsproject/obs-studio/ubuntu jammy main
  Active apt repos in: /etc/apt/sources.list.d/official-package-repositories.list
    1: deb https: //mirror.fcix.net/linuxmint-packages virginia main upstream import backport
    2: deb http: //mirror.math.ucdavis.edu/ubuntu jammy main restricted universe multiverse
    3: deb http: //mirror.math.ucdavis.edu/ubuntu jammy-updates main restricted universe multiverse
    4: deb http: //mirror.math.ucdavis.edu/ubuntu jammy-backports main restricted universe multiverse
    5: deb http: //security.ubuntu.com/ubuntu/ jammy-security main restricted universe multiverse
Info:
  Processes: 448 Uptime: 3d 21h 58m wakeups: 10581 Memory: 15.3 GiB used: 10.33 GiB (67.5%)
  Init: systemd v: 249 runlevel: 5 Compilers: gcc: 11.4.0 alt: 11/12
  Client: Unknown python3.10 client inxi: 3.3.13

regarding the comment about the 60" monitor, this was immediately after disconnecting from a 60" monitor. i've used the same sets of monitors in my various work locations for many years, but the glitch is recent. i would be very hesitant to attribute it to the monitors.

[SMG]

System information:

I suggest trying a newer kernel series as it likely will have newer Intel drivers and any adjustments those might have for external monitor ports.

Instructions for upgrading to the 6.5 kernel:

• Open Update Manager.
• Select View > Linux Kernels and click Continue.
• Make sure 6.5 is selected on the left panel and then click the top-most option on the right panel. An "Install" button will appear.
• Install the kernel and then reboot for it to become active.

Maybe that will help.

I also recommend doing a bit of cleaning because your system is getting rather full. That can affect graphics performance. (And adding new kernels can add to that fullness.)
Partition:
ID-1: / size: 233.18 GiB used: 199.36 GiB (85.5%) fs: ext4 dev: /dev/sda2
ID-2: /boot/efi size: 511 MiB used: 6.1 MiB (1.2%) fs: vfat dev: /dev/sda1

I usually recommend keeping it below 70-75% full. Anything getting close to 90% is getting close to when you can start running into issue logging in.

The below is a bit surprising to me given how much memory your computer has, but it may not have any relevance to this issue.

Code: Select all

Swap:
  ID-1: swap-1 type: file size: 2 GiB used: 381.9 MiB (18.6%) priority: -2 file: /swapfile

[taguely]

Thank you for the time and effort.

I've upgraded to the newest kernel version (didn't know it wasn't enabled already). I'll try things out for a bit and get back if there continue to be issues or close the post if it seems to be addressed.

Re: the swap comment, what part of that is concerning? Is it the size of the swap file or how much is used? If the latter, it's probably because I had a KVM instance running/suspended when I grabbed the report. After rebooting (before powering the instance back on), swap usage is 0.0%.

file space usage is also because i run a number of different VM instances (required as part of my job). i believe i have 5-6 different instances (between kvm and multipass) present, though only one runs at any given time.

[SMG]

I've upgraded to the newest kernel version (didn't know it wasn't enabled already).

I gave you directions for the HWE (HardWare Enablement) kernel. That has to be manually activated to be used. The 5.15 kernel is the LTS (Long Term Support) kernel and comes on the non-Edge ISOs.

Re: the swap comment, what part of that is concerning? Is it the size of the swap file or how much is used? If the latter, it's probably because I had a KVM instance running/suspended when I grabbed the report. After rebooting (before powering the instance back on), swap usage is 0.0%.

The KVM instance would explain it. I was thinking it would be unusual for "normal" usage to be dipping that much into swap.

file space usage is also because i run a number of different VM instances (required as part of my job). i believe i have 5-6 different instances (between kvm and multipass) present, though only one runs at any given time.

Those can be big and that would explain that.

The system is set up to give warnings when you start getting close to the possibility of having issues logging in.

[taguely]

thank you so much, i very much appreciate your help.
patrick

[taguely]

Unfortunately, the graphics glitching happened again today. The exact sequence of events was: I was using my laptop in my office connected to a USB-C dock with two external monitors attached (laptop screen disabled, lid closed); I suspended and unplugged from there and moved to a classroom; upon resume, the screen was glitching wildly, even before I connected to the Crestron system in the classroom. Before the kernel upgrade, I was able to often fix the problem by toggling display settings or by repeating the suspend/resume cycle. In this case, I spent a good 5 minutes trying different display setting toggles, multiple suspend/resume cycles, but the visual glitching persisted. The classroom display was not affected, so I was able to still hold my class, but I had a glitchy screen in front of me the entire time. I don't know if there will be anything useful, but I'm including system information copy/paste from when I first resumed and encountered the glitching this time.

I would very much appreciate any additional suggestions.

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System:
  Kernel: 6.5.0-26-generic x86_64 bits: 64 compiler: N/A Desktop: Cinnamon 6.0.4 tk: GTK 3.24.33
    wm: muffin vt: 7 dm: LightDM 1.30.0 Distro: Linux Mint 21.3 Virginia base: Ubuntu 22.04 jammy
Machine:
  Type: Laptop System: LENOVO product: 20RA004YUS v: ThinkPad E14 serial: <superuser required>
    Chassis: type: 10 serial: <superuser required>
  Mobo: LENOVO model: 20RA004YUS v: SDK0J40697 WIN serial: <superuser required> UEFI: LENOVO
    v: R16ET40W (1.26 ) date: 11/23/2023
Battery:
  ID-1: BAT0 charge: 41.2 Wh (100.0%) condition: 41.2/45.7 Wh (90.1%) volts: 12.3 min: 11.1
    model: SMP 5B10W138 type: Li-poly serial: <filter> status: Not charging cycles: 165
CPU:
  Info: quad core model: Intel Core i5-10210U bits: 64 type: MT MCP smt: enabled
    arch: Comet/Whiskey Lake note: check rev: C cache: L1: 256 KiB L2: 1024 KiB L3: 6 MiB
  Speed (MHz): avg: 2150 high: 2400 min/max: 400/4200 cores: 1: 2400 2: 2400 3: 2400 4: 2400
    5: 2400 6: 2400 7: 2400 8: 400 bogomips: 33599
  Flags: avx avx2 ht lm nx pae sse sse2 sse3 sse4_1 sse4_2 ssse3 vmx
Graphics:
  Device-1: Intel CometLake-U GT2 [UHD Graphics] vendor: Lenovo driver: i915 v: kernel ports:
    active: eDP-1 empty: DP-1,HDMI-A-1,HDMI-A-2 bus-ID: 00:02.0 chip-ID: 8086:9b41 class-ID: 0300
  Device-2: IMC Networks Integrated Camera type: USB driver: uvcvideo bus-ID: 1-8:3
    chip-ID: 13d3:5415 class-ID: 0e02
  Display: x11 server: X.Org v: 1.21.1.4 driver: X: loaded: modesetting unloaded: fbdev,vesa
    gpu: i915 display-ID: :0 screens: 1
  Screen-1: 0 s-res: 1920x1080 s-dpi: 96 s-size: 508x286mm (20.0x11.3") s-diag: 583mm (23")
  Monitor-1: eDP-1 model: Chi Mei Innolux res: 1920x1080 hz: 60 dpi: 158
    size: 309x173mm (12.2x6.8") diag: 354mm (13.9") modes: 1920x1080
  OpenGL: renderer: Mesa Intel UHD Graphics (CML GT2) v: 4.6 Mesa 23.2.1-1ubuntu3.1~22.04.2
    direct render: Yes
Audio:
  Device-1: Intel Comet Lake PCH-LP cAVS vendor: Lenovo driver: snd_hda_intel v: kernel
    bus-ID: 00:1f.3 chip-ID: 8086:02c8 class-ID: 0403
  Sound Server-1: ALSA v: k6.5.0-26-generic running: yes
  Sound Server-2: PulseAudio v: 15.99.1 running: yes
  Sound Server-3: PipeWire v: 0.3.48 running: yes
Network:
  Device-1: Realtek RTL8111/8168/8411 PCI Express Gigabit Ethernet vendor: Lenovo driver: r8169
    v: kernel pcie: speed: 2.5 GT/s lanes: 1 port: 3000 bus-ID: 04:00.0 chip-ID: 10ec:8168
    class-ID: 0200
  IF: enp4s0 state: down mac: <filter>
  Device-2: Realtek RTL8822CE 802.11ac PCIe Wireless Network Adapter vendor: Lenovo
    driver: rtw_8822ce v: N/A pcie: speed: 2.5 GT/s lanes: 1 port: 2000 bus-ID: 05:00.0
    chip-ID: 10ec:c822 class-ID: 0280
  IF: wlp5s0 state: up mac: <filter>
  IF-ID-1: mpqemubr0 state: down mac: <filter>
  IF-ID-2: virbr0 state: down mac: <filter>
Drives:
  Local Storage: total: 238.47 GiB used: 198.31 GiB (83.2%)
  ID-1: /dev/sda vendor: SanDisk model: SD8SN8U-256G-1006 size: 238.47 GiB speed: 6.0 Gb/s
    type: SSD serial: <filter> rev: 0006 scheme: GPT
Partition:
  ID-1: / size: 233.18 GiB used: 198.3 GiB (85.0%) fs: ext4 dev: /dev/sda2
  ID-2: /boot/efi size: 511 MiB used: 6.1 MiB (1.2%) fs: vfat dev: /dev/sda1
Swap:
  ID-1: swap-1 type: file size: 2 GiB used: 8 KiB (0.0%) priority: -2 file: /swapfile
USB:
  Hub-1: 1-0:1 info: Hi-speed hub with single TT ports: 12 rev: 2.0 speed: 480 Mb/s
    chip-ID: 1d6b:0002 class-ID: 0900
  Device-1: 1-8:3 info: IMC Networks Integrated Camera type: Video driver: uvcvideo
    interfaces: 2 rev: 2.0 speed: 480 Mb/s power: 500mA chip-ID: 13d3:5415 class-ID: 0e02
  Hub-2: 2-0:1 info: Super-speed hub ports: 6 rev: 3.1 speed: 10 Gb/s chip-ID: 1d6b:0003
    class-ID: 0900
Sensors:
  System Temperatures: cpu: 63.0 C pch: 51.0 C mobo: N/A
  Fan Speeds (RPM): N/A
Repos:
  Packages: 2358 apt: 2347 snap: 11
  No active apt repos in: /etc/apt/sources.list
  Active apt repos in: /etc/apt/sources.list.d/obsproject-obs-studio-jammy.list
    1: deb [signed-by=/etc/apt/keyrings/obsproject-obs-studio-jammy.gpg] https: //ppa.launchpadcontent.net/obsproject/obs-studio/ubuntu jammy main
  Active apt repos in: /etc/apt/sources.list.d/official-package-repositories.list
    1: deb https: //mirror.fcix.net/linuxmint-packages virginia main upstream import backport
    2: deb http: //mirror.math.ucdavis.edu/ubuntu jammy main restricted universe multiverse
    3: deb http: //mirror.math.ucdavis.edu/ubuntu jammy-updates main restricted universe multiverse
    4: deb http: //mirror.math.ucdavis.edu/ubuntu jammy-backports main restricted universe multiverse
    5: deb http: //security.ubuntu.com/ubuntu/ jammy-security main restricted universe multiverse
Info:
  Processes: 429 Uptime: 2d 32m wakeups: 104 Memory: 15.3 GiB used: 8.55 GiB (55.9%) Init: systemd
  v: 249 runlevel: 5 Compilers: gcc: 11.4.0 alt: 11/12 Client: Unknown python3.10 client
  inxi: 3.3.13

[SMG]

Unfortunately, the graphics glitching happened again today. The exact sequence of events was: I was using my laptop in my office connected to a USB-C dock with two external monitors attached (laptop screen disabled, lid closed); I suspended and unplugged from there and moved to a classroom; upon resume, the screen was glitching wildly, even before I connected to the Crestron system in the classroom.

To what screen are you resuming if you suspended with the laptop screen turned off and you are not yet attached to any screen in the classroom? What exactly is the sequence of buttons/keys/settings changes you are using?

The classroom display was not affected, so I was able to still hold my class, but I had a glitchy screen in front of me the entire time.

So the external port was not affected; only the eDP port was affected?

Glitching screens do not show up in inxi output. There might be messages in journalctl. You could try running

Code: Select all

journalctl -b | grep -i "drm\|i915\|00:02.0"

and checking the timestamp for recent/new messages.

The below is a bit on the warm side, but maybe it's residual from larger monitors you had attached prior to moving the laptop.

Code: Select all

Sensors:
  System Temperatures: cpu: 63.0 C pch: 51.0 C mobo: N/A
  Fan Speeds (RPM): N/A

[taguely]

i think i've figured out that this is a faulty internal connection between the motherboard and the screen. if i reposition the screen (tilt it slightly further forward or backward), i can make the glitching stop.