lkml.org 
[lkml]   [2003]   [Apr]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] M68k IDE updates
On Mon, 14 Apr 2003, Paul Mackerras wrote:
> Alan Cox writes:
> > This looks the wrong place to fix this problem Geert. The PPC
> > folks have the same issues with byte order on busses but you
> > won't see ifdefs in the core IDE code for it.
> >
> > Fix your __ide_mm_insw/ide_mm_outsw macros and the rest happens
> > automatically.
>
> As I understand it, on some platforms (including some PPC platforms,
> but not powermacs) one needs to byteswap drive ID data but not the
> normal sector data. Or vice versa. Whether drive ID data needs
> byte-swapping comes down to how the drive is attached to the bus. The
> conventions used by other systems that we need to interoperate with
> (e.g. other OSes, or just older kernels) determine whether normal
> sector data needs byte-swapping or not.
>
> Since __ide_mm_insw doesn't get told whether it is transferring normal
> sector data or drive ID data, it can't necessarily do the right thing
> in both situations.

Indeed. Ataris and Q40/Q60s have byteswapped IDE busses, but they expect
on-disk data to be that way, for compatibility with e.g. TOS.

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

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 13:34    [from the cache]
©2003-2014 Jasper Spaans. Advertise on this site