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k0ss4

Member

Registered: 2021-02-05

Posts: 17

Broken hardware acceleration on lightDM [SOLVED]

Hello,
This is my second thread on hardware acceleration. I have a really weird issue on xfce4 with lightdm. When i launch the web browser(brave) and try to play some game(shake&fidget for example) the cpu usage by brave gpu process goes to like 50%. I switched to sddm and everything works fine(6% cpu usage on the game mentioned before). Also it happens only after setting something(displays positions in my case) in nvidia-setting and saving it into /etc/X11/xorg.conf. Is it a known problem with lightdm? How can i solve it? Thank you

My specs:
GPU: RTX 2070 SUPER
GPU driver: nvidia-dkms 460.39
CPU: Ryzen 7 2700x
Kernel: 5.10.16-zen
(It also happens on normal kernel)

Last edited by k0ss4 (2021-02-17 12:31:55)

Lone_Wolf

Member

From: Netherlands, Europe

Registered: 2005-10-04

Posts: 11,911

Re: Broken hardware acceleration on lightDM [SOLVED]

Also it happens only after setting something(displays positions in my case) in nvidia-setting and saving it into /etc/X11/xorg.conf.

Does using the xorg.conf from nvidia-settings result in the 50% cpu use ?

---

Disliking systemd intensely, but not satisfied with alternatives so focusing on taming systemd.

(A works at time B)  && (time C > time B ) ≠  (A works at time C)

V1del

Forum Moderator

Registered: 2012-10-16

Posts: 21,657

Re: Broken hardware acceleration on lightDM [SOLVED]

No this is a race condition that has a chance to happen on every boot with any setup, mostly on fast SSDs, to fix that set up your mkinitcpio to include the nvidia kernel modules as mentioned in: https://wiki.archlinux.org/index.php/NV … de_setting (the parameter is optional, the modules line in mkinitcpio is important). Also if you indeed want to use nvidia-settings generated xorg.confs you need to ensure they include a

Section "Files"    
    ModulePath "/usr/lib/nvidia/xorg"
    ModulePath "/usr/lib/xorg/modules"
EndSection

in the file somewhere (... though it'd probably more sustainable to just create your own xorg config adjusting only the necessary part, without the kitchen sink approach of nvidia-settings generated configs)

k0ss4

Member

Registered: 2021-02-05

Posts: 17

Re: Broken hardware acceleration on lightDM [SOLVED]

Does using the xorg.conf from nvidia-settings result in the 50% cpu use ?

Yes

to fix that set up your mkinitcpio to include the nvidia kernel modules as mentioned in: https://wiki.archlinux.org/index.php/NV … de_setting

Just setting the modules an doing mkinitcpio -p linux-zen fixed the problem. Thank you