fretis: please check these links:
I also stumbled above this error: Win2K will always reverts the IDE channel to PIO.
When I boot linux, the drive is working perfectly in DMA mode. This happened after I tried to read in a CD that was not burned correctly (overburn didn't work). Here a quote from the above link:
PIO mode is enabled by default in the following situations:
For repeated DMA errors. Windows XP will turn off DMA mode for a device after encountering certain errors during data transfer operations. If more that six DMA transfer timeouts occur, Windows will turn off DMA and use only PIO mode on that device.
In this case, the user cannot turn on DMA for this device. The only option for the user who wants to enable DMA mode is to uninstall and reinstall the device.
Windows XP downgrades the Ultra DMA transfer mode after receiving more than six CRC errors. Whenever possible, the operating system will step down one UDMA mode at a time (from UDMA mode 4 to UDMA mode 3, and so on).
The solution is to uninstall & reboot the affected IDE channel. Win2K will re-install the driver upon reboot. Then activate the DMA in the Hardware Manager from the System control panel as decribed here:
Reboot again to make the DMA change effective.