Jakob Zweiblumen's questions

System freezes on startup after plugged in via dock. On second (third, and so on) boot - everything is OK. If the laptop is powered via direct a/c cable - everything is OK

18.04 LTS had the same problem. Sometimes I could see the user list after boot, and that was the final stage before freezing

20.04 live version has the same problem. It passes stage "checking disks", and freezes on the splash screen

Windows 10 doesn't have this problem - so it looks like hardware is OK

GRUB is updated with

GRUB_CMDLINE_LINUX_DEFAULT="--verbose nosplash debug"

Last thing I see before the freeze is

ucsi_acpi USBC000:00: PPM NOT RESPONDING
ucsi_acpi USBC000:00: PPM init failed (-110)
amdgpu 0000:02:00.0: GPU pci config reset

Sometimes after that, I can see something like "A start job is running for", and it can be a different number of different services each time

Are there any suggestions about what could it be or what can I check to get more info about the issue?

Hardware: lenovo thinkpad e480 laptop (intel+amd hybrid graphics) + lenovo thinkpad usb-c dock + dell u2415 monitor. Bios / dock firmware: latest versions installed

If external monitor is connected to displayport or vga on dock (no HDMI / dvi ports there), I get running bright pixels on monitor, and sometimes monitor just randomly turns off and on (sometimes few times per minute, sometimes few times per hour). Tested on Ubuntu 18.04 / 19.04, got the same result

On Windows 10 I still get running pixels (but almost invisible) when refresh rates are 59/60 for laptop/external displays, and everything works perfectly when refresh rates are 60/60 - so it looks like hardware is OK

On Ubuntu (both 18.04 and 19.04) everything works fine when external monitor is connected to HDMI port on laptop (no displayport there) - so it looks like intel graphics drivers are OK

Tried to:

• install appropriate displaylink drivers for 18.04 (nothing changes)
• install appropriate displaylink drivers for 19.04 (nothing changes)
• install amdgpu drivers (failed, uninstall failed too)
• change laptop refresh rate (didn't help, but pixels are "running" differently for different rate)
• set refresh rates 60/60 (didn't work, those are not possible values)
• set kernel parameter i915.edp_vswing=2 (didn't help)
• set i915.preliminary_hw_support=1 (didn't help)
• set intel_idle.max_cstate (to different values, didn't help)
• use vga_switcheroo to switch to amd graphics card (failed, commands didn't change anything, even in su mode)

How can I fix this issue with dock displayports / vga?