[Openchrome-devel] [PATCH 1/2] via: fix line compare

[James Simmons]

> Line compare register writes are obviously wrong:
> 
> Register 0x33 is written with value 0x05 using mask 0x06
> It causes left side of the screen to be garbled and shifted right
> at least on K8M890CE.

Yeap, your right. I just looked at the hardware specs and noticed 
the line compare comment is completely wrong above register 0x33.
Bits 0-2 are for HSYNCH Adjuster. The value you have is for shifting
by 1 character. I will update your patch for that comment update.
 
> Register 0x09 is written using mask 0xff, overwriting bit 5
> (which is bit 9 of vblank_start register).
> It causes blue horizontal bar on top of screen and blank bar in the middle
> at least on K8M890CE.

Yeap you are correct. 

> Fix the writes to match viafb.
> 
> Signed-off-by: Ondrej Zary <linux at rainbow-software.org>

Acked-by: James Simmons <jsimmons at infradead.org>

> --- a/drivers/gpu/drm/via/via_display.c
> +++ b/drivers/gpu/drm/via/via_display.c
> @@ -678,11 +678,11 @@ via_crtc_mode_set(struct drm_crtc *crtc, struct 
> drm_display_mode *mode,
>  	/* line compare should set all bits = 1 (extend modes) */
>  	svga_wcrt_mask(VGABASE, 0x07, BIT(4), BIT(4));
>  	/* line compare should set all bits = 1 (extend modes) */
> -	svga_wcrt_mask(VGABASE, 0x09, BIT(6), 0xFF);
> +	svga_wcrt_mask(VGABASE, 0x09, BIT(6), BIT(6));
>  	/* line compare should set all bits = 1 (extend modes) */
>  	svga_wcrt_mask(VGABASE, 0x35, BIT(4), BIT(4));
>  	/* line compare should set all bits = 1 (extend modes) */
> -	svga_wcrt_mask(VGABASE, 0x33, 0x05, 0x06);
> +	svga_wcrt_mask(VGABASE, 0x33, 0x06, 0x07);
>  	/* extend mode always set to e3h */
>  	vga_wcrt(VGABASE, 0x17, 0xE3);
>  	/* extend mode always set to 0h */
> 
> -- 
> Ondrej Zary
> 
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