Hi,
After upgrading kernel from 5.3 series to 5.6.16 something seems to prevent me from achieving high resolutions with the ast driver.
With 5.6.16:
$ xrandr Screen 0: minimum 320 x 200, current 1600 x 1200, maximum 1920 x 2048 VGA-1 connected primary 1600x1200+0+0 (normal left inverted right x axis y axis) 519mm x 324mm 1600x1200 60.00* 1680x1050 59.95 1280x1024 75.02 60.02 1440x900 59.89 1280x800 59.81 1024x768 75.03 60.00 800x600 75.00 60.32 640x480 75.00 59.94 1920x1200_60.0 59.95
If I try to change to that manually added high-res mode, I get: xrandr: Configure crtc 0 failed
With 5.3 series I've this:
Screen 0: minimum 320 x 200, current 1920 x 1200, maximum 1920 x 2048 VGA-1 connected primary 1920x1200+0+0 (normal left inverted right x axis y axis) 519mm x 324mm 1920x1200 59.95*+ 1600x1200 60.00 1680x1050 59.95 1280x1024 75.02 60.02 1440x900 59.89 1280x800 59.81 1024x768 75.03 60.00 800x600 75.00 60.32 640x480 75.00 59.94 1920x1200_60.0 59.95
As I've had issues in getting EDID reliably from the monitor, I provide it on kernel command-line (the one dumped from the monitor I use). In addition, I've another workaround for past issues related to EDID which always adds that 1920x1200_60.0 mode but now I cannot use even it to enter a high-res mode.
If you need some additional info or want me to test a patch, just let me know (but some delay is expected in testing patches). Thanks.