Score:2

Ubuntu 21.10 and hardware acceleration problem for external monitor as a primary display

uz flag

I recently upgraded to 21.10 and note that browsers run really slow only for the external monitors. I disable hardware acceleration in the browser's settings and it solved the problem. Only for browsers) There are a lot of programs with the same problem where I can't disable hardware acceleration - playing videos in the telegram messenger for example.

I checked 2 combinations:

Laptop + Dell P2415Q 24" (4k) USB-C Display Port -> Display Port
Laptop + Philips FHD HDMI -> HDMI

I tried all available proprietary nvidea drivers from 460 to 495 and checked with and without the fractional scaling.

I didn't have similar problem on previous ubuntu (21.04) and it also works perfectly on windows.

[EDIT] The external monitor has problem with hardware acceleration only when it chosen as a primary display.

What should I check?

System info NVIDEA

ng flag
Have you found a solution? I'm having the same problem. My monitor is Dell P2720DC and laptop Lenovo IdeaPad Gaming 3 with 1650Ti.
sergei.sss avatar
uz flag
@vitaliy unfortunately no
ng flag
I've just figured out a workaround that works for me. Turns out the problem appears only when in Hybrid graphics mode, so I switched to using Nvidia gpu exclusively and everything works fine. I have a suspicion that this happens because my laptop can output to external display only from Nvidia GPU and not from an integrated one. This doesn't explain why it's working fine when display is not primary though, so this is probably a software bug.
sergei.sss avatar
uz flag
@vitaly You workaround works. But for this case the fractional scaling doesn't work (I use 100% for built-in and 200% for external monitor and tried with 470 and 490 nvidea drivers). Your Dell P2720DC has 2560 × 1440 and Lenovo IdeaPad Gaming probably has FHD. Do you use fractional scaling? Does it work normally?
cradox23 avatar
vn flag
Thanks! Crucial info is that it's occuring when the 4K display is set as primary. I wasted an hour trying different configs (drivers and kernels) and nothing worked. Going back to laptop as my primary screen at least solves this issue. Without hardware acceleration it's painfully sluggish.
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