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SubjectRe: [PATCH] hgafb oopses
On Fri, 9 Nov 2001, Bakonyi Ferenc wrote:
> Somebody submitted a patch against 2.4.13 which broke hgafb. That patch
> called isa_memset() and isa_writeb() with an _already_ mapped address.
> So that address was mapped twice -> oops.

Sorry... Anyway, the old code was broken too, since it wasn't portable.

(Why did no one told me? I did receive an additional patch to make hgafb work
again after I posted the first version to linux-kernel, which I did
incorporate in the final version).

> The patch below is against 2.4.15-pre1. It resolves the ISA address
> confusion, replaces scr_{read|write} functions with isa_{read|write},
> and elimiates a cosmetic compiler warning about suggested parens.

But it does some other Bad Things(TM): putting ISA memory _adresses_ and
_16_bit_ values in _unsigned_chars_ is not good for your health...

> --- linux-2.4.15-pre1/drivers/video/hgafb.c Fri Nov 9 12:22:42 2001
> +++ linux/drivers/video/hgafb.c Fri Nov 9 12:26:33 2001
> @@ -312,10 +312,10 @@
> static int __init hga_card_detect(void)
> {
> int count=0;
> - u16 *p, p_save;
> - u16 *q, q_save;
> + unsigned char p, p_save;
> + unsigned char q, q_save;
^^^^^^^^^^^^^
>
> - hga_vram_base = VGA_MAP_MEM(0xb0000);
> + hga_vram_base = 0xb0000;
> hga_vram_len = 0x08000;
>
> if (request_region(0x3b0, 12, "hgafb"))
> @@ -325,14 +325,14 @@
>
> /* do a memory check */
>
> - p = (u16 *) hga_vram_base;
> - q = (u16 *) (hga_vram_base + 0x01000);
> + p = hga_vram_base;
> + q = hga_vram_base + 0x01000;
>
> - p_save = scr_readw(p); q_save = scr_readw(q);
> + p_save = isa_readw(p); q_save = isa_readw(q);
>
> - scr_writew(0xaa55, p); if (scr_readw(p) == 0xaa55) count++;
> - scr_writew(0x55aa, p); if (scr_readw(p) == 0x55aa) count++;
> - scr_writew(p_save, p);
> + isa_writew(0xaa55, p); if (isa_readw(p) == 0xaa55) count++;
> + isa_writew(0x55aa, p); if (isa_readw(p) == 0x55aa) count++;
> + isa_writew(p_save, p);

Gr{oetje,eeting}s,

Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@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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