Bug 475904 - screen goes black if display scale < 100% in kernel 6.5
Summary: screen goes black if display scale < 100% in kernel 6.5
Status: RESOLVED UPSTREAM
Alias: None
Product: kwin
Classification: Plasma
Component: wayland-generic (show other bugs)
Version: 5.27.8
Platform: Manjaro Linux
: NOR normal
Target Milestone: ---
Assignee: KWin default assignee
URL:
Keywords: wayland-only
Depends on:
Blocks:
 
Reported: 2023-10-21 04:23 UTC by fluffy bunny
Modified: 2024-08-20 16:36 UTC (History)
3 users (show)

See Also:
Latest Commit:
Version Fixed In:
Sentry Crash Report:


Attachments
screenshot of display setting (274.22 KB, image/png)
2023-10-21 04:23 UTC, fluffy bunny
Details

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Description fluffy bunny 2023-10-21 04:23:49 UTC
Created attachment 162469 [details]
screenshot of display setting

hello,

i have issue related to display settings : the screen goes black when all these conditions are met :

state = after booting (SDDM is fine, but after that, only black) or after display goes sleep (after idle for several minutes)
scale = below 100% (see attached screenshot, if scale = 100%, then issue doesn't occurr)
kernel = 6.5 (in 6.4, issue doesn't occurr)
DE = wayland (in X11, i can't set the scale to below 100%)

when issue occurs, laptop can still receive keyboard instruction (i can send ctrl+alt+t then input "shutdown now" to turn off laptop) just display doesn't show anything

i need to set below 100%, because some apps are misbehaving in 1366x768 resolution (that's max resolution on my laptop)

hardaware spec = AMD A9-9420 with discrete GPU radeon 530
Comment 1 Zamundaaa 2023-10-25 12:09:56 UTC
That's quite odd. KWin's buffer size doesn't change depending on the scale, so the display should behave the same with any scale.
Can you still switch to a different tty when the screen isn't showing anything?
Comment 2 fluffy bunny 2023-10-27 08:36:48 UTC
hello,

thanks for response

could you explain : "switch different tty"?

when the screen doesn't show anything, it can still receive command from keyboard. e.g. i input ctrl+alt+t (from physical keyboard) it opens terminal (even i can't see it with my eye), after that i type "shutdown now", then the laptop shuts down / power off

those are recorded in journalctl, i assume the session is active, the CPU is active, when screen doesn't show anything
Comment 3 Zamundaaa 2023-10-27 13:31:18 UTC
If you press ctrl+alt+F4, your desktop should switch to the virtual terminal 4. You can get back to your desktop with ctrl+alt+F2 (or F1, or F7, depends a bit on the distro. Just try all of them until you see your desktop again).

If you switch to a different virtual terminal while the screen is black and it stays black, that means there's 100% something wrong with the kernel driver. If it starts working again - and especially if it keeps working if you switch back to the desktop - it might be a bug in KWin
Comment 4 fluffy bunny 2023-10-29 12:03:39 UTC
hello,

i have tried : make the screen black (by rebooting in scale = 80% & kernel = 6.5)

these keys combination have no any effect (still black)

ctrl+alt+F1
ctrl+alt+F2
ctrl+alt+F3
ctrl+alt+F4
ctrl+alt+F6

but ctrl+alt+F6 brings to "terminal like" display, but no GUI
Comment 5 Bug Janitor Service 2023-11-13 03:45:46 UTC
Dear Bug Submitter,

This bug has been in NEEDSINFO status with no change for at least
15 days. Please provide the requested information as soon as
possible and set the bug status as REPORTED. Due to regular bug
tracker maintenance, if the bug is still in NEEDSINFO status with
no change in 30 days the bug will be closed as RESOLVED > WORKSFORME
due to lack of needed information.

For more information about our bug triaging procedures please read the
wiki located here:
https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging

If you have already provided the requested information, please
mark the bug as REPORTED so that the KDE team knows that the bug is
ready to be confirmed.

Thank you for helping us make KDE software even better for everyone!
Comment 6 Zamundaaa 2023-11-13 13:55:53 UTC
When you see the terminal, if you log in and execute "loginctl", it should show you the active sessions, and the TTY the graphical session is on. If you switch to that tty, do you see something again, or does it stay black?
Comment 7 fluffy bunny 2023-11-18 01:19:32 UTC
ah, sorry, i haven't checked this bug for a while

i have execute loginctl, & it shows tty1 is active (only 1 session is active)

and i have tried ctrl+alt+F1 (to return to tty1), and it is still black
Comment 8 fluffy bunny 2023-11-19 03:43:31 UTC
hello, i would like to update about this issue :

the latest stable update from manjaro fixes this, now, in kernel 6.6, black screen does not occurr anymore

but i don't know which part of the update that solved the problem

& i don't know about condition in kernel 6.5, i have uninstalled it
Comment 9 Nate Graham 2023-11-29 17:30:09 UTC
Cool, thanks!