Re: [PATCH #upstream-fixes] pata_cmd64x: revert commit d62f5576

[Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>]

On Tuesday 17 August 2010 05:39:17 pm Alan Cox wrote:
> > The old problem is much less severe tho.  The introduced regression
> > causes oops while the old bug probably doesn't show itself too often.
> 
> If ever
> 
> > Does it really need to merge the DMA timings too?  If the device can't
> > do certain timing, it's PIO configuration should reflect that so
> > merging PIO part only should be enough for PIO configuration, no?
> 
> The timing code knows about DMA/PIO constraints itself. The whole mucking
> around passing both timings is just bogus.
> 
> Pass pair->dma_mode only and it'll work out the PIO for you. Not that it
> matters - no real hardware has a DMA mode with a slower address setup
> than its PIO mode.

There were some PIO3/MWDMA1 devices out in the wild (Iomega ZIP IIRC)..

Anyway the patch has never been submitted upstream:

*) I have absolutely no time to support it or related changes

*) it was not critical enough and/or important for other related work
   (it is more important in atang/ide2libata context)

> and for UT just stick in some value (eg 33000) so it works in PCI clocks

Exactly, ->udma is never used by the driver itself..

Thanks.
--
Bartlomiej Zolnierkiewicz