[PATCH] drm/ast: change resolution may cause screen blurred

[Jean Delvare]

On Wed,  3 Oct 2018 14:57:47 +0800, Y.C. Chen wrote:
> From: "Y.C. Chen" <yc_chen at aspeedtech.com>
> 
> The value of pitches is not correct while calling mode_set.
> The issue we found so far on following system:
> - Debian8 with XFCE Desktop
> - Ubuntu with KDE Desktop
> - SUSE15 with KDE Desktop
> 
> Signed-off-by: Y.C. Chen <yc_chen at aspeedtech.com>
> ---
>  drivers/gpu/drm/ast/ast_mode.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/gpu/drm/ast/ast_mode.c b/drivers/gpu/drm/ast/ast_mode.c
> index 5e77d45..f06aae7 100644
> --- a/drivers/gpu/drm/ast/ast_mode.c
> +++ b/drivers/gpu/drm/ast/ast_mode.c
> @@ -568,6 +568,7 @@ static int ast_crtc_do_set_base(struct drm_crtc *crtc,
>  	}
>  	ast_bo_unreserve(bo);
>  
> +	ast_set_offset_reg(crtc);
>  	ast_set_start_address_crt1(crtc, (u32)gpu_addr);
>  
>  	return 0;

Tested-by: Jean Delvare <jdelvare at suse.de>
Reviewed-by: Jean Delvare <jdelvare at suse.de>

I did experience the mentioned display corruption on resolution change
on an ASPEED 1100/2050 chipset, under Plasma (KDE). I can confirm that
the patch above prevents it.

There is also a report in openSUSE's bugzilla:
  https://bugzilla.opensuse.org/show_bug.cgi?id=1112963
where the user tested the patch above successfully on an ASPEED 2500
chipset.

Can we get the fix merged now?

Thanks,
-- 
Jean Delvare
SUSE L3 Support