We are using a VAR-SOM-DUAL from Variscite with i.MX6DualLite and experience graphics artifacts when we rotate the screen by 180 degrees. The graphics artifacts appear around the mouse pointer while moving the mouse (see attached photo, there shouldn't be anything at the top of the screen, only at the bottom).
We were using Debian Jessie for years on a 180 degrees rotated screen (xrandr -o inverted) without any issues, no graphics artifacts. Recently we tried to upgrade to a more up-to-date OS for several reasons, but any more up-to-date OS has these graphics artifacts as soon as we rotate the screen. We already contacted Variscite's support and they suggest it is a regression in the Vivante libraries. Our Debian Jessie build uses v5 of the Vivante libraries and all the new options we tried (Debian Stretch, Yocto Thud) use version 6. Variscite was even able to reproduce this with the NXP SabreSD board and official images.
We are able to remove the artifacts by applying a small scale to the screen while rotating it (see screen shifted after xrandr rotation), but then the transition between the screens of our application and all our animations are very slow. So this workaround is not suitable.
I found a couple of different, older questions here that describe a similar issue, but none of them provide a working solution for the problem:
- VAR-SOM-DUAL with i.MX6DualLite
- Yocto Thud
- X11 version 1.19.6
- Vivante 6.2.4.p1.8
- Linux 4.14.78
- Screen: 1024x600 over HDMI
- xrandr -o inverted to rotate the screen, because setting in xorg.conf does not work (see Vivante: trying to rotate display in xorg.conf: Assert Failed )
Is this a regression in the Vivante libraries v6? Or is there any way to work around this issue?