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

[Thomas Zimmermann]

Hi

Am 13.09.22 um 17:15 schrieb Wang Yugui:
[...]
>>>
>>> so I tried to revert patch of mgag200 driver in batch of 2 or 3, the I
>>> noticed the patch 'Subject: drm/mgag200: Remove special case for G200SE
>>> with <2 MiB' and then tried this dirty fix.
>>
>> Oh, great work! Thank you. From looking at the screenshot that you provided, it seems as if the 24-bit mode setting is broken. I'm not sure why the G200SE workaround applies to a G200ER, but we'll see.
> 
> I tested 'preferred_depth = 32' too. it works on T630 too.
> 
> so both 16 and 32 work, but 24 failed on DELL/T630.

I tried on my test machine with a 5.19 kernel and found that 32-bit and 
24-bit pixels work, but 16-bit looks incorrect.

What are the results if you boot your kernel 5.19.3 with the parameter 
video=1024x768-24? This should enable 24-bit pixels.

How does video=1024x768-16 look with the 5.19 kernel?

Best regards
Thomas

> 
> diff --git a/drivers/gpu/drm/mgag200/mgag200_mode.c
> b/drivers/gpu/drm/mgag200/mgag200_mode.c
> index 225cca2ed60e..563e3ab05fbc 100644
> --- a/drivers/gpu/drm/mgag200/mgag200_mode.c
> +++ b/drivers/gpu/drm/mgag200/mgag200_mode.c
> @@ -1070,7 +1070,7 @@ int mgag200_modeset_init(struct mga_device *mdev, resource_size_t vram_available
> 
>          dev->mode_config.max_width = MGAG200_MAX_FB_WIDTH;
>          dev->mode_config.max_height = MGAG200_MAX_FB_HEIGHT;
> -       dev->mode_config.preferred_depth = 24;
> +       dev->mode_config.preferred_depth = 32;
>          dev->mode_config.fb_base = mdev->vram_res->start;
>          dev->mode_config.funcs = &mgag200_mode_config_funcs;
> 
> Best Regards
> Wang Yugui (wangyugui at e16-tech.com)
> 2022/09/13
> 
> 
> 

-- 
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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