From: Paul Mackerras <paulus@samba.org>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>,
Linus Torvalds <torvalds@transmeta.com>,
Linux Kernel Development <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] M68k IDE updates
Date: Mon, 14 Apr 2003 09:43:23 +1000 (EST) [thread overview]
Message-ID: <16025.63003.968553.194791@nanango.paulus.ozlabs.org> (raw)
In-Reply-To: <1050243002.24186.7.camel@dhcp22.swansea.linux.org.uk>
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.
It's very possible that there are some PPC platforms for which IDE is
borken right now - I strongly suspect this would be the case for the
Tivo at least, and probably several other embedded PPC platforms.
Paul.
next prev parent reply other threads:[~2003-04-13 23:34 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-04-13 13:06 [PATCH] M68k IDE updates Geert Uytterhoeven
2003-04-13 14:10 ` Alan Cox
2003-04-13 23:43 ` Paul Mackerras [this message]
2003-04-14 8:39 ` Geert Uytterhoeven
2003-04-14 9:19 ` Benjamin Herrenschmidt
2003-04-14 9:24 ` Geert Uytterhoeven
2003-04-14 12:19 ` Alan Cox
2003-04-14 12:21 ` Alan Cox
2003-04-14 13:44 ` Geert Uytterhoeven
2003-04-14 16:03 ` Alan Cox
2003-04-15 4:45 ` Jamie Lokier
2003-04-15 8:11 ` Geert Uytterhoeven
2003-04-15 9:23 ` Jörn Engel
2003-04-15 9:52 ` Geert Uytterhoeven
2003-04-14 12:48 ` Alan Cox
2003-04-14 12:48 ` Alan Cox
2003-04-14 17:44 ` Linus Torvalds
2003-04-14 19:54 ` Geert Uytterhoeven
2003-04-14 22:31 ` Paul Mackerras
2003-04-15 8:14 ` Geert Uytterhoeven
2003-04-21 16:55 ` Geert Uytterhoeven
2003-04-22 14:49 ` Alan Cox
2003-04-22 13:55 Mudama, Eric
[not found] <Pine.GSO.4.21.0304221802570.16017-100000@vervain.sonytel.be>
2003-04-23 11:27 ` Richard Zidlicky
2003-04-23 11:04 ` Alan Cox
2003-04-23 20:19 ` John Bradford
2003-04-24 9:47 ` Richard Zidlicky
2003-04-24 11:26 ` Geert Uytterhoeven
2003-04-24 13:14 ` Richard Zidlicky
2003-04-24 14:11 ` Geert Uytterhoeven
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