Display artifacts on Thinkpad T420

[benrkts]

Hi,

I am getting random glitches/artifacts on my screen, like this:

It seems to happen when the system is busier (though CPU temp is not much elevated) but is overall random. Often, I have to restart X to make them go away. It doesn't happen in Linux, so I think it is a FreeBSD issue.

This is a Thinkpad T420 with stock Intel HD 3000 graphics and an upgraded display and VGA cable. I am running 13.0-release with drm-kmod-g20190710_1 and xf86-video-intel-2.99.917.916_1,1 installed. /boot/modules/i915kms.ko is being loaded automatically, and I do not load anything relevant from rc.conf. In xorg.conf, I have this:

Section "Device"
        Identifier      "Card0"
        Driver          "intel"
        Option          "TearFree" "true"
EndSection

However, I can also comment this out. Performance suffers, and the glitches are less frequent, but they still show up.

For reference:

Xorg.0.log, with the above lines commented out
dmesg
rc.conf
loader.conf

I would really appreciate any help.

 

[zoltan]

Hi. When you switch between multiple operating systems, such as from Windows to Linux, then from Linux to BSD, and so on, or remove and reattach the battery, it's sometimes a good idea to perform an EC reset. I'm not sure how it's done on a ThinkPad, but on my HP laptop, I remove the battery and unplug the power cord, then hold down the power button for 10-20 seconds. It's similar to a hard reset. It isn't always effective, but sometimes things build up in the EC and mess with the hardware, causing weird artifacts on the screen.