Hi
Am 08.07.20 um 12:05 schrieb Ilpo Järvinen:
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.
Thanks for reporting. It's not a bug, but a side effect of atomic modesetting.
During pageflips, the old code used to kick out the currently displayed framebuffer and then load in the new one. If that failed, the display went garbage.
In v5.6-rc1, we merged atomic modesetting for ast. This means that screen updates are more reliable, but we have to over-commit resources. Specifically, we have to reserve space for two buffers in video memory while a pageflip happens. 1920x1200@32 are ~9MiB of framebuffer memory. If your device has 16 MiB of VRAM, there's no space left for the second framebuffer. Hence, the resolution is no longer supported.
On the positive side, you can now use Wayland compositors with ast. Atomic modesetting adds the necessary interfaces.
Best regards Thomas
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.