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Re: D-I Etch+1/2 CD images (was: D-I Etch+1/2 kernel selection)

On Sat, 9 Feb 2008, Michael Schmitz wrote:
> > Note that recently some byteswapping code was removed (the generic one
> > you can specify on the kernel command line, to read normal disks on
> > e.g. Atari and Atari disks on normal systems), but I did check that one
> > didn't impact us.
> hdb=swap hasn't worked for me last I tried a while back, and it is missed
> indeed. When did it get removed?

commit 9e47be0c97f7357b80e91dc0632e9cce2eb025e0
Author: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Date:   Sat Jan 26 20:13:09 2008 +0100

    ide: remove broken disk byte-swapping support
    Remove broken disk byte-swapping support:
    - it can cause a data corruption on SMP (or if using PREEMPT on UP)
    - all data coming from disk are byte-swapped by taskfile_*_data() which
      results in incorrect identify data being reported by /proc/ide/ and IOCTLs
    - "hdx=bswap/byteswap" kernel parameter has been broken on m68k host drivers
      (including Atari/Q40 ones) since 2.5.x days (because of 'hwif' zero-ing)
    - byte-swapping is limited to PIO transfers (for working with TiVo disks on
      x86 machines using user-space solutions or dm-byteswap should result in
      much better performance because DMA can be used)
    For previous discussions please see:
    [ I have dm-byteswap device mapper target if somebody is interested
      (patch is for 2.6.4 though but I'll dust it off if needed). ]

> That would actually be nice to have as an optional patch - or maybe it
> could be handled by a special 'crypto' module and cryptoloop mounting the
> disk? Plugging an Atari disk into a PC would be a great way for Christian
> to get the necessary install files copied on his Falcon disk ...

So you want the dm-byteswap device mapper target mentioned above...

> > > BTW: the borked ATA_HD_CONTROL register bug will alsi hit macide (and
> > > perhaps others). gayle.c passes the sanitized control port value to
> > > gayle_setup_ports so it's in the clear.
> >
> > Thx, good to know! Didn't check Gayle since last weekend...
> Bhudda is in the clear as well IIRC, FWIW.

Thx! Aranym is happy after fixing up ATA_HD_CONTROL. Patch will follow...



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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