Re: CD-ROM patches versus IDE DMA

Jens Axboe (axboe@image.dk)
Sun, 7 Nov 1999 15:41:40 +0100


On Sat, Nov 06 1999, Brion Vibber wrote:
> Jens, for some reason your CD-ROM patch doesn't get along with DMA for
> my IDE drives. :( When booting 2.2.13 with the November 4 patch, I get IRQ
> timeouts resulting in disabled DMA during the partition check.
> ...
> Partition check:
> hda:hda: irq timeout: status=0xd0 { Busy }
> hda: DMA disabled
> hdb: DMA disabled
> ide0: reset: success

Thanks for the nice report. The DMA timeouts are a known problem
with that patch, it's fixed in the new one. Could you try this
patch:

http://www.kernel.dk/nov7-2.2.diff

> not making significant changes outside the CD code where of course the
> meat of the patch lies. I tried a quick obvious hack, returning this
> line to ide.c:
> - del_timer(&hwgroup->timer); /* Is this needed?? */

That was safe. It was a del_timer from inside the timer handler,
which is not needed.

> but it changed nothing, so it looks like it was one of the safe-looking
> changes (moving the timeout value to the drive struct instead of a
> parameter to ide_set_handler) and I can't tell what's wrong with them.

Yes, nasty timeout handling. The patch above takes a somewhat
different approach.

-- 
*  Jens Axboe <axboe@image.dk>
*  Linux CD-ROM Maintainer
*  http://www.kernel.dk

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