Re: 2.6.23.17 & 2.6.24.5 and maybe earlier: pata_marvell: need todisable DMA to get rid of '(ATA bus error)', 'ata7.00: status: { DRDY ERR }','ata7.00: error: { ICRC ABRT }'

[Robert Hancock]

Alan Cox wrote:
> > > libata.dma=3 will stop DMA being used for CF devices (except those that
> > > decide to pretend to be ATA classes). This one comes up a lot as many CF
> > > adapters are simply not adequate for UDMA.
> > Perhaps the kernel could do this automatically once it sees the
> > status code?
>
> We then hurt all the people with perfectly good working UDMA CF devices.
> The kernel will eventually fall back from UDMA to PIO but it favours
> working hardware by default.

I suspect they meant fall back on seeing the ABRT/ICRC error combination 
- which it does, eventually. Falling back on one occurrence would be too 
aggressive, though, as they can happen once in a blue moon, so there's 
little reason to slow down a working setup forever because of it..
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