When trying to use
hdparm to activate the DMA mode, I got the error message
This could be solved by unsetting _all_ other IDE chipset drivers than the driver
for the Intel chipsets (CONFIG_BLK_DEV_PIIX=y), even CONFIG_IDE_GENERIC is not set.
If CONFIG_BLK_DEV_IDEDMA_PCI=y and CONFIG_BLK_DEV_IDEDMA_FORCED=y are set, it is
not even necessary to use
hdparm for the activation.