https://bugs.kde.org/show_bug.cgi?id=478670
Bug ID: 478670
Summary: black screen when starting plasma after logging in to
sddm on Lenovo P14sGen4/amd
Classification: Plasma
Product: kwin
Version: 5.27.10
Platform: Fedora RPMs
OS: Linux
Status: REPORTED
Severity: normal
Priority: NOR
Component: general
Assignee: kwin-bugs-n...@kde.org
Reporter: slartibar...@gmail.com
Target Milestone: ---
I recently bought a new lenovo laptop P14s/gen4 amd 7840u with integrated
radeon graphics and OLED (2880x1800) screen
Using fedora39 (latest updates, kernel 6.6.6 and 6.6.7) i encounter a black
screen when booting and when trying to start the kde-session after sddm-login
Let me give some details:
The problem seems to be the oled-laptop screen, which (maybe) provides improper
edid data for the boot process.
Using
ls /sys/class/drm/card*
i found the name of my screen (card1-eDP-1) and using this
cat /sys/class/drm/card1-eDP-1/edid | edid-decode
i found those timing settings:
Detailed Timing Descriptors:
DTD 1: 2880x1800 90.001438 Hz 16:10 169.203 kHz 500.840000 MHz
(302 mm x 189 mm)
Hfront 8 Hsync 32 Hback 40 Hpol P
Vfront 8 Vsync 8 Vback 64 Vpol N
DTD 2: 2880x1800 60.000958 Hz 16:10 169.203 kHz 500.840000 MHz
(302 mm x 189 mm)
Hfront 8 Hsync 32 Hback 40 Hpol P
Vfront 8 Vsync 8 Vback 1004 Vpol N
For the bootup procedure (and for seeing any kind of display output at all) i
'fixed' grub with this
GRUB_TERMINAL_OUTPUT="gfxterm"
GRUB_GFXMODE="2880x1800@60"
GRUB_CMDLINE_LINUX="rd.luks.uuid=luks-5b8a9e98-d8a7-4d51-b04c-88113d062065
rd.lvm.lv=vg0/root video=card1-eDP-1:2880x1800@60 rhgb vconsole.font=ter-128b"
This gives me the graphical grub menu and (note the missing 'quiet' in the
commandline) some output in text form when booting - including the graphical
screen asking for the luks-encryption password.
(This, btw, if you remove 'rhgb' as well, is never shown on the laptop screen
in text format - you can enter the necessary password on a black screen without
any feedback and it continues booting. So, the rhgb is an improvement here)
The sddm login screen also appears, i can use the options (reboot, more, etc)
and can successfully log-in.
BUT ... Then plasma only shows a black screen again.
What also works is entering a vconsole (ctrl-alt F3) as long as you did not(!)
logon to sddm.
After logging in, vconsole as well as plasma stays black with no way to recover
any output on the display.
I can, however, add 'nomodeset' to the grub-commandline.
Then, plasma starts successfully, i can switch to vconsoles back and forth.
BUT (yes, another but)... this is very bad, as i cannot change any display
resolution or screen brightness with plasma.
Interestingly, a fedora-39 live usb boot seems to work pretty nice, plasma
comes up after sddm, i can change the default 200% zoom to any other level or
change the screen resolution and refresh rates using systemsettings
Questions:
How can i use plasma without 'nomodeset'?
What does the live-usb iso of fedora make so much better than the fresh
fedora39 installation it did by itself on this machine???
What do i need to change to use my new laptop???
Any help is appreciated,
if there is any additional information i can provide please ask...
----
currently i am using a fresh net-install with
Operating System: Fedora Linux 39
KDE Plasma Version: 5.27.9
KDE Frameworks Version: 5.111.0
Qt Version: 5.15.11
Kernel Version: 6.6.6-200.fc39.x86_64 (64-bit)
but i also tried updating to kernel 6.6.7 and kde 5.27.10, adding rpmfusion
repos, added zawertun-kde repo for other updates, but this did not help at all
for this problem.
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