Re: Parallel ATA with libata status with the patches I'm working on

Benjamin Herrenschmidt
2005-11-04T23:20:17Z

On Fri, 2005-11-04 at 23:10 +0000, Russell King wrote:
> On Fri, Nov 04, 2005 at 01:41:06PM +0000, Alan Cox wrote:
> > While writing the new sl82c05 driver I noticed a real nasty lurking in
> > the old code. According to the errata docs you have to reset the DMA
> > engine every transfer to work around chip errata. It also says that this
> > resets any other ATA transfer in progress.
> >
> > If both channels are in use there is no locking between the channels to
> > stop a reset on one channel as DMA begins making a mess of the other
> > channel. Looks like serialize should be set on the driver ?
>
> Possibly, though benh needs to comment. (I think benh has the only
> hardware which has the possibility of both channels - the NetWinder
> only has one channel with one disk.)

I don't have this hw anymore, it was a design I worked on for my
previous employer, years ago, I don't have access to it anymore and the
company doesn't exist anymore.

Ben.