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

[Ilpo Järvinen]

Hi,

Yes, I can build custom kernels and test but I won't have time for that 
before the end of September so I'll do it only then.

And thanks a lot :-).

-- 
 i.


On Thu, 17 Sep 2020, Thomas Zimmermann wrote:

> 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.
> > 
> > 
> 
>