how to fix tearing with FVWM/AMD/picom? [SOLVED]

ExecutorElassus

I have xorg, FVWM, an AMD Radeon FX 5700, with picom installed. I have some obnoxious tearing issues in all cases: scrolling, moving video, gaming, etc. Can anybody give me advice for how to tweak my system to fix this? My xorg.conf file is blank, so it's just using default settings.

Thanks for the help,

EE

NeddySeagoon · Posted: Sat Oct 30, 2021 11:51 am Post subject:

ExecutorElassus,

Tearing is a video artefact cased by updating the pixel buffer at the same time as its being used to refresh the image on the screen.
Its unsightly but harmless.

Its normally addressed by using two (or more) separate pixel buffers so that one is used to refresh the screen while the other is updated with the next image.
The buffers are switched during the frame blanking.

There are a few arrangements where this is not possible.
You only have one frame time to draw the next image. That's 16.6ms at 60Hz. What happens when the next frame is not ready?
Normally, the old frame is displayed again and you get frame dropping.

In the case of Optimus and the like, the two GPUs need to cooperate here and in Linux, that's not always very good.

Share your Xorg.0.log on a pastebin, so we can see what's happening.

Xorg uses double buffering by default unless there is not enough video RAM but that's not been a problem for many years now.
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.

ExecutorElassus · Posted: Sat Oct 30, 2021 1:57 pm Post subject:

Hi Neddy,

when I said the file was blank, what I really mean is that the file /etc/X11/xorg.conf doesn't exist. So the xorg-server isn't getting any settings at all. Is this a valid pastebin link for you?

https://paste.c-net.org/PlumbingBadmouth

Thanks for the help,

EE
(and yes, I realize that mostly it's just ugly, but for gaming it's really bothersome)

NeddySeagoon · Posted: Sat Oct 30, 2021 2:51 pm Post subject:

ExecutorElassus,

ExecutorElassus · Posted: Sat Oct 30, 2021 3:26 pm Post subject:

Hi Neddy,

better pastebin: https://dpaste.com/BBZ67KVM2

I have two monitors, each with a resolution of 1920x1200.

But you should be able to see it from the pastebin.

Thanks for your help,

EE

NeddySeagoon · Posted: Sat Oct 30, 2021 5:41 pm Post subject:

ExecutorElassus,

ExecutorElassus · Posted: Sat Oct 30, 2021 5:52 pm Post subject:

does that need to be in xorg.conf? If so, since that file does not exist, is there anything else I need to put in that file besides that to get it to work?

NeddySeagoon · Posted: Sat Oct 30, 2021 6:28 pm Post subject:

ExecutorElassus,

xorg.conf and xorg.conf.d/* are merged. Normally xorg.conf.d/ contains xorg.conf fragments.
Either way works. Mix and match works too.

You need a

ExecutorElassus · Posted: Sat Oct 30, 2021 6:48 pm Post subject:

So, I created the file "/etc/X11/xorg.conf.d/10-devices.conf", containing only: