VGA console endian bug

Geert Uytterhoeven geert at linux-m68k.org
Fri Aug 10 18:41:39 EST 2001


On Thu, 9 Aug 2001, Hollis Blanchard wrote:
> These two patches came from Daniel Berlin on July 9. They completely resolve
> the VGA console backwards-endian problem for me on PPC. If they have Geert's
> seal of approval ;) can they be committed?
>
> -Hollis
>
> --- linuxppc_2_4_devel/include/asm-ppc/vga.h.old	Thu Aug  9 11:49:23 2001
> +++ linuxppc_2_4_devel/include/asm-ppc/vga.h	Thu Aug  9 11:49:42 2001
> @@ -37,6 +37,9 @@
>
>  #define VT_BUF_HAVE_MEMCPYW
>  #define scr_memcpyw	memcpy
> +#define VT_BUF_HAVE_MEMCPYF
> +#define scr_memcpyw_to memcpy
> +#define scr_memcpyw_from memcpy
>
>  #endif /* !CONFIG_VGA_CONSOLE && !CONFIG_MDA_CONSOLE */

The first I cannot approve: if scr_{write,read}w() swap bytes, how can it work
if scr_memcpyw_{to,from}() don't swap bytes?

> --- linuxppc_2_4_devel/drivers/video/fbcon.c.old	Thu Aug  9 11:45:10 2001
> +++ linuxppc_2_4_devel/drivers/video/fbcon.c	Thu Aug  9 11:46:23 2001
> @@ -2028,13 +2028,13 @@
>  	if (!conp->vc_can_do_color)
>  	    *p++ ^= 0x0800;
>  	else if (conp->vc_hi_font_mask == 0x100) {
> -	    u16 a = *p;
> +	    u16 a = scr_read(p);
>  	    a = ((a) & 0x11ff) | (((a) & 0xe000) >> 4) | (((a) & 0x0e00) << 4);
> -	    *p++ = a;
> +	    scr_write(a, p++);
>  	} else {
> -	    u16 a = *p;
> +	    u16 a = scr_read(p);
>  	    a = ((a) & 0x88ff) | (((a) & 0x7000) >> 4) | (((a) & 0x0700) << 4);
> -	    *p++ = a;
> +	    scr_write(a, p++);
>  	}
>  	if (p == (u16 *)softback_end)
>  	    p = (u16 *)softback_buf;

Approved :-)

And where's the 3rd patch? I once posted a patch to fix a similar bug in
drivers/char/console.c.

Gr{oetje,eeting}s,

						Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
							    -- Linus Torvalds


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