Comment 27 for bug 1849084

Sorry, I made a mistake I'm running kubuntu (not Ubuntu like mentioned in #24).

Indeed I can confirm that with a switched off compositor resume will work. And I can confirm that resume only fails the first time after a power up reset of the computer. When the screen turn blank after the first time resume I do a login via SSH and initiate a reboot. After this all suspend / resume cycles will work perfectly.

It is strange that a compositor's bug will affect the amdgpu driver module. This snippet of journalctl log shows a line emitted by the amdgpu module where a test runs into a timeout:

Feb 27 10:43:02 Lin kernel: PM: suspend exit
Feb 27 10:43:02 Lin systemd-sleep[2125]: System resumed.
Feb 27 10:43:02 Lin kernel: [drm] pstate TEST_DEBUG_DATA: 0xB7F60000
Feb 27 10:43:02 Lin kernel: ------------[ cut here ]------------
Feb 27 10:43:02 Lin kernel: WARNING: CPU: 2 PID: 2191 at /build/linux-hwe-LNyirI/linux-hwe-5.3.0/drivers/gpu/drm/amd/amdgpu/../display/dc/dcn10/dcn10_hw_sequencer.c:932 dcn10_verify_allow_pstate_change_high+0x37/0x2d0 [amdgpu]

I've attached the log parts of a failing resume (compositor is switched on):
* 10:40 Start
* 10:42 Suspend 1st time
* 10:43 Resume 1st time
* 10:45 reboot
* 10:46 Suspend 2nd time
* 10:47 Resume second time

I think I'll try the workaround mentioned in https://forum.manjaro.org/t/lenovo-laptop-wont-resume-after-sleep/105233/27