1366x768 screen resolution broken, all other resolutions OK

[Somebody someone]

Hi,

After upgrade from Ubuntu Mate 19.10 to Ubuntu Mate 20.04 i cannot use a resolution of 1366x768. Screenshot attached. I am using an Asus vivoBook laptop with Amd Ryzen 3 and a Radeon Vega Graphics AMD.

I found someone in reddit reporting the same problem: https://www.reddit.com/r/UbuntuMATE/comments/ggq8g5/problem_with_resolution_1366x768_with_ubuntu_mate/

All other screen resolutions OK.

Many thanks

[johnny lee (johnnyl33-k)]

It happened to me as well on my lenovo ideapad laptop with Xubuntu 20.04, and I came with a weird but functional workaround: I opened the display window, selected the 1366x768 resolution, rotation: inverted and reflection: horizontal and vertical, then applied. Worked!

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[mike-g2 (mikeg-utk)]

I have the same issue. As mentioned in reddit thread in OP, the login screen displays properly at 1366x768. I'm running MATE so I'm not sure how to implement the workaround @johnnyl33-k mentions for Xubuntu since there are no reflection options. I will note setting rotation to 'upside-down' in Control Center->Monitor Preference does not suffer from the tearing the 'normal' rotation does. It's just hard to work upside down!

[mike-g2 (mikeg-utk)]

A little investigation and the following implements johnnyl33-k's workaround from the command line.

$ xrandr --output eDP --reflect xy --rotate inverted --mode 1366x768

[mike-g2 (mikeg-utk)]

Here's some output that perhaps is helpful

# Normal orientation with tearing:
$ xrandr
Screen 0: minimum 320 x 200, current 1366 x 768, maximum 16384 x 16384
eDP connected primary 1366x768+0+0 (normal left inverted right x axis y axis) 344mm x 193mm
   1366x768 60.06*+ 40.04
   1280x720 60.06
   1024x768 60.06
   800x600 60.06
   640x480 60.06
HDMI-A-0 disconnected (normal left inverted right x axis y axis)

# Workaround configuration
$ xrandr
Screen 0: minimum 320 x 200, current 1366 x 768, maximum 16384 x 16384
eDP connected primary 1366x768+0+0 inverted X and Y axis (normal left inverted right x axis y axis) 344mm x 193mm
   1366x768 60.06*+ 40.04
   1280x720 60.06
   1024x768 60.06
   800x600 60.06
   640x480 60.06
HDMI-A-0 disconnected (normal left inverted right x axis y axis)