mgag200 broken on kernel-6.0-rc3 on DELL/T620

[Thomas Zimmermann]

Hi

Am 14.09.22 um 16:58 schrieb Wang Yugui:
[...]
>> 24-bit works on my G200HE and G200 test machines. Maybe the G200ER has a bug.
>>
>> When I try 16-bit depth, the display works, but is way too dark. No fiddling with the LUT tables fixes this. It's 90s hardware, so it should support 16-bit framebuffers well, but there's no obvious bug to be seen.
>>
>> I guess, we could remove 16 and 24 bit support for now if nothing else helps.
> 
> 
> maybe better if we revert 73f54d5d9682 (drm/mgag200: Remove special case
> for G200SE with <2 MiB)

Could you please test the attached patch on the 6.0-rc3 kernel? It 
should force the driver to a correct color format if no kernel 
parameters are given.

Best regards
Thomas

> 
> because there is no test result on device G200_SE
> 
> static unsigned int mgag200_preferred_depth(struct mga_device *mdev)
> {
>         if (IS_G200_SE(mdev) && mdev->vram_fb_available < (2048*1024))
>                 return 16;
>         else
>                 return 32;
> }
> 
> Best Regards
> Wang Yugui (wangyugui at e16-tech.com)
> 2022/09/14
> 

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