Blocky artifacts (Xorg i915drm.ko 12.1-RELEASE NUC7i7BNH Iris Plus 650)

[TRDragony]

I am no C-developer and I switched from Debian to FreeBSD yesterday, so please forgive the inavoidable lack of non-included mandatory information you will probably want.

Hardware: NUC7i7BNH (newest BIOS version flashed)

GPU: Iris Plus 650

Software:
Xorg (installed via pkg install Xorg)
XFCE4 (installed via pkg install xfce4)

Configuration: Unchanged. No Xorg config generated or something else.

Problem:
First start with startxfce4 worked, but graphics were slow. So I did "pkg install drm-kmod", but after reboot FreeBSD went into an endless reboot-loop. I then had to find out how to get rid of the kernel driver via rescue shell, but failed due to lack of FreeBSD knowledge, so I reinstalled FreeBSD. Then I read about ports and installed the port via "cd /usr/ports/graphics/drm-kmod ; make install". Then I did "kldload /boot/modules/i915kms.ko" and got a bunch of messages saying success. Now startxfce4 works and moving windows via mouse drag & drop is fast. YAY!
But the problem still existing are some weird chess-pattern like block-artifacts on ONLY the nearly top of the screen. I were unable to measure them out, but I think they are 64x64 px. They don't start at the far top y position 0, but maybe on y position 300 or so and stop at y position 600 or so. They exist for only one frame, so you only see them when playing videos or moving windows around in that area. While I can just ignore it when working, its really annoying when playing videos and I need to get rid of that.
I am booting via UEFI, so I already am having a VGA console right after boot. In console mode (without Xorg loaded), that phenomenon seems not to appear, but its hard to check because I can't move windows around.
That phenomenon also appears on TWM window manager, so its no XFCE4 issue either.

I wonder what I still can do. Is /usr/ports/graphics/drm-devel-kmod newer? Is drm the source of that problem at all? Where to go from here? Help please :(

If you need additional information, please tell me the exact things I have to enter in the console. Thank you very much.

[TRDragony]

The area looks like this. The whole image is representing the whole display and its just a scetch so you get an idea.

Display resolution is 2560x1600. I also tried on another display with 2560x1440. Same problem.

[valpackett]

that's a weird artifact to have, but have you enabled compositing in xfce4 settings?

[TRDragony]

Yes it is enabled. I disabled it to test and the artifacts have disappeared! Thank you. That was an easy solution. Of course I don't have the fancy compositor anymore with semi-transparent windows, but the artifacts were so massively annoying that I am glad that I got rid of them!

Any chance this issue will be fixed in the future? Does someone need more information on this?

[valpackett]

wait how does it happen with twm then o_0 I assumed it would only happen without compositing.

I guess my suggestions would be

• try a different x11 compositor like compton
• check if there are artifacts on kmscube, on wayland (wayfire, sway etc.)
• try a newer mesa
• try drm-devel-kmod (on -CURRENT kernel)

[TRDragony]

The problem only appears with ENABLED compositing.

[valpackett]

Also try newer xorg and newer xfwm..

In the xorg update thread https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=196678 there are mentions of an xfce compositing bug

[TRDragony]

Thank you. I will follow your advices and upgrade a few packages.

…

On Tue, 18 Feb 2020 16:04:30 -0800 myfreeweb ***@***.***> wrote: Also try newer xorg and newer xfwm.. In the xorg update thread https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=196678 there are mentions of an xfce compositing bug

[jbeich]

GPU: Iris Plus 650

If you're using xf86-video-intel (deprecated) instead of modesetting DDX shipped as part of xorg-server then update or update. For example, SNA in xf86-video-intel may fail which is going to cause graphical artifacts in GL applications (see #32 for glxgears screenshot), so X11 compositor can be affected.