Created attachment 141697 [details]
4.19 rc4 boot log (black screen)
AMDGPU fails to initialise the graphics card with mainline kernel 4.19, from rc1 to rc4, resulting in a black screen on boot.
4.18.8 boots to the desktop without any fatal errors, and functions as expected.
The regression happened some time before 4.19 rc1 but after the 4.18 release.
Graphics card is:
01:00.0 VGA compatible controller : Advanced Micro Devices, Inc. [AMD/ATI] Bonaire XT [Radeon HD 7790/8770 / R7 360 / R9 260/360 OEM] [1002:665c]
I attempted to bisect it, but I kept hitting another (possibly unrelated) bug that would cause a panic on boot and thus was unable to.
Attached are the kernel logs from both 4.18.8 and 4.19 rc4.
Running the latest available firmware for this card from the git repo.
Created attachment 141698 [details]
4.18.8 boot log (working)
Created attachment 143205 [details]
4.19.0 Debian kernal boot log (external screen working)
I can reproduce this with
00:01.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Carrizo (rev c4)
03:00.0 Display controller: Advanced Micro Devices, Inc. [AMD/ATI] Bonaire XT [Radeon R9 M280X] (rev 80)
on a “Lenovo ideapad Y700-ACZ”.
When I boot into the released Linux 4.19.0 from Debian I get a blank screen, however today I discovered that if you have an external displayed plugged during boot-up that display will be successfully enabled and you can then log in as usual. The internal laptop display will not ever be enabled however and checking under *Systemsettings* → *Monitor Settings* (KDE) will not show it either. Also the entire system will feel very sluggish (not CPU or disk related, I checked) and is only usable with lots of patience. On shutdown the system will then hang (nothing about this in system logs unfortunately).
Remove amdgpu.dpm=1 from your kernel command line. The default dpm implementation changed in 4.19.
(In reply to Alex Deucher from comment #3)
> Remove amdgpu.dpm=1 from your kernel command line. The default dpm
> implementation changed in 4.19.
and setting dpm=1 overrides that resulting in different behavior. power management is always enabled by default. the dpm option is only for debugging and switching between implementations for asics that contain multiple implementations.
Using the latest Debian kernel (4.19.0-2, which apparently corresponds to Linux version 4.19.16, with 4.19.0-1 having corresponded to 4.19.13) this issue does not affect me anymore.
I looked through the kernel commits between the versions but none looked very related, there was some stuff about DP MST which maybe somehow relevant since the display is connected using eDP. Dunno.
Anyways, works for me now.