On Wed, Oct 24, 2012 at 11:57:46AM +0100, Alan Cox wrote:

Which is an ATA layer bug - adev->dma_mode should never be called
without a DMA mode in normal use.

Ok, it looks like this would take a while to fix.

Alan, what is your suggestion for a proper fix, uncomment XFER_PIO_SLOW
and drop to it with a big warning that ACPI is giving botched
information on those chips and people should try using the
platform-specific driver if they want better/optimal speeds?

Thanks.

-- 
Regards/Gruss,
    Boris.