On Sun, Feb 04, 2001 at 03:36:14PM -0500, Thor Lancelot Simon wrote:
> On Sun, Feb 04, 2001 at 11:33:10AM -0800, Jason R Thorpe wrote:
> > On Sun, Feb 04, 2001 at 02:26:29PM -0500, Thor Lancelot Simon wrote:
> > 
> >  > pciide totally loses with transfers larger than 64k.  I'm surprised that siop
> >  > doesn't work -- what limits it to 64k?
> > 
> > Generally, this is because the max number of segments created in a DMA
> > map are ((MAXPHYS / PAGE_SIZE) + 1) (+ 1 to handle transfers that aren't
> > page-aligned).
> 
> So, if I increase MAXPHYS, this should increase, too, right?  pciide
> still doesn't work -- I thought, from reading the driver, that the hardware
> had a 64K constraint.  No?

Hum, there's a 64k boundary constraint, but bus_dma should take care of this
(more descriptors). However the count register is 8bits, so you're limited
to at most 255 sectors (127.5KB). 

--
Manuel Bouyer <bouyer@antioche.eu.org>
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