Re: [PATCH] highmem I/O for ide-pmac.c

From: Jens Axboe (axboe@suse.de)
Date: Thu Sep 12 2002 - 01:59:03 EST

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On Thu, Sep 12 2002, Paul Mackerras wrote:
> Jens Axboe writes:
>
> > The above refers to ide_toggle_bounce() export, pmac_* variant is
> > exactly the same. Sorry if that wasn't clear.
>
> Why does ide_toggle_bounce assume we can only do DMA to highmem if
> drive->media == ide_disk? At the moment I can't see any reason why
> the ide-pmac interface can't do DMA to highmem for a cdrom, for
> instance.

Because it requires changes to the personality driver (ie ide-disk,
ide-cd, etc). I only did those changes to ide-disk, didn't figure it was
worthwhile to do for ide-cd for instance. It's not exactly a
high-performance media :-)

If the device is always in dma mode, no changes are needed. It's when
you drop to pio the problem arises, and all the interrupt handlers need
to be fixed.

-- Jens Axboe

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