Stuttery scrolling with NVIDIA and GLX backend after v12.3 (regression)

[bubbleguuum]

Sorry to be again the bringer of bad NVIDIA news :/

After you fixed #1265, I compiled latest next branch and... scrolling is noticeably stuttery, while it was silk smooth with v12.3 (config: GLX backend with vsync enabled). That issue is of course not caused by the #1265 fix.

Digging into it, I would not be surprised it is caused by this large commit a54adb6.

I thought this could be the removal of libdrm but that's not it, I tested that v12.3 compiled with or without it is identically smooth.

[yshui]

were you using the legacy backends?

[bubbleguuum]

Nope, I use the same config for both v12.3 (no issue) and next (issue):

backend = "glx"
vsync = true

[yshui]

hmm, if that commit has caused any problems i am having a hard time to see why it would only affect nvidia 🤔 because the rendering code path should be unchanged.

[bubbleguuum]

It's very well possible it is not NVIDIA specific. Let me try picom compiled before and after that commit to check if it is the cause.

[bubbleguuum]

Looks like it is a latter commit after all. Will have to git bisect to find it but I'll have to learn how to use it first.

[bubbleguuum]

It seems to be caused by 8065c1f

[yshui]

ah, yep, that commit is wrong. that probably also explains why picom is using a bit more cpu over here. thanks for catching this.