drm/ast something ate high-res modes (5.3->5.6 regression)

[Thomas Zimmermann]

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.

Are you able to build and run a test kernel?

I'm seriously considering moving ast to the SHMEM memory manager, which
would restore the higher resolutions.

If you're able to test, you need the git tree drm-tip/drm-tip and the
attached patch.

Alternatively, I've pushed all to

  https://gitlab.freedesktop.org/tzimmermann/linux/-/tree/ast-shmem

You'd have to checkout the tree and switch to the ast-shmem branch.

Please report back if that solves the issue for you.

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.
> 
> 

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Felix Imendörffer
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