SATA Conflict with PATA DMA

[Esben Stien <b0ef@esben-stien.name>]

I'm having problems enabling DMA for my PATA HD.

hdparm -d1 /dev/hdb reports: 
HDIO_SET_DMA failed: Operation not permitted

Of course, I'm super user. Nothing is printed in dmesg. 

I'm on linux-2.6.16 and motherboard is Fujitsu Siemens D1561 with an
ICH5. I also have a SATA hd in the computer and this only happens when
the SATA hd is there. If I remove the SATA HD, then I can enable DMA
for the PATA hd.

Both the SATA and the PATA are very new. 

# zcat /proc/config.gz |grep -i dma
CONFIG_GENERIC_ISA_DMA=y
CONFIG_ISA_DMA_API=y
CONFIG_BLK_DEV_IDEDMA_PCI=y
# CONFIG_BLK_DEV_IDEDMA_FORCED is not set
CONFIG_IDEDMA_PCI_AUTO=y
# CONFIG_IDEDMA_ONLYDISK is not set
CONFIG_BLK_DEV_IDEDMA=y
# CONFIG_IDEDMA_IVB is not set
CONFIG_IDEDMA_AUTO=y
# CONFIG_SCSI_PDC_ADMA is not set

Any pointers as to what I can try?

-- 
Esben Stien is b0ef@e     s      a             
         http://www. s     t    n m
          irc://irc.  b  -  i  .   e/%23contact
          [sip|iax]:   e     e 
           jid:b0ef@    n     n