Re: Silicon Image 3112A SATA trouble

[Jeff Garzik]

Jens Axboe wrote:
> On Sun, Nov 30 2003, Vojtech Pavlik wrote:
>
> > On Sun, Nov 30, 2003 at 06:10:06PM +0100, Jens Axboe wrote:
> >
> >
> > > On Sun, Nov 30 2003, Jeff Garzik wrote:
> > >
> > > > Bartlomiej Zolnierkiewicz wrote:
> > > >
> > > > > On Sunday 30 of November 2003 17:51, Jens Axboe wrote:
> > > > >
> > > > > > > Tangent:  My non-pessimistic fix will involve submitting a single sector
> > > > > > > DMA r/w taskfile manually, then proceeding with the remaining sectors in
> > > > > > > another r/w taskfile.  This doubles the interrupts on the affected
> > > > > > > chipset/drive combos, but still allows large requests.  I'm not terribly
> > > > > >
> > > > > > Or split the request 50/50.
> > > > >
> > > > >
> > > > > We can't - hardware will lock up.
> > > >
> > > > Well, the constraint we must satisfy is
> > > >
> > > > 	sector_count % 15 != 1
> > >
> > > 	(sector_count % 15 != 1) && (sector_count != 1)
> > >
> > > to be more precise :)
> >
> > I think you wanted to say:
> >
> > 	(sector_count % 15 != 1) || (sector_count == 1)
>
>
> Ehm no, I don't think so... To my knowledge, sector_count == 1 is ok. If
> not, the hardware would be seriously screwed (ok it is already) beyond
> software fixups.


Now that you've kicked my brain into action, yes, sector_count==1 is ok. 
 It's all about limiting the data FIS...  and with sector_count==1 
there is no worry about the data FIS in this case.

	Jeff


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