Enable ata DMA on a PowerMac G4?

[Torfinn Ingolfsen]

hello,
how do I enable DMA for my ata drives on a PMac G4?

root at kg-g4# uname -a
FreeBSD kg-g4.kg4.no 7.0-20051105-SNAP FreeBSD 7.0-20051105-SNAP #0: Sat Nov  5 04:33:52 UTC 2005     root at macmini.ptree32.com.au:/usr/obj/usr/src/sys/GENERIC  powerpc

root at kg-g4# dmesg | grep ata
ata0 mem 0x1f000-0x1ffff,0x8a00-0x8aff irq 19 on macio0
ata1 mem 0x20000-0x20fff,0x8b00-0x8bff irq 20 on macio0
ata2 mem 0x21000-0x21fff,0x8c00-0x8cff irq 21 on macio0
ad0: 58644MB <IC35L060AVER07 0 ER6OA44A> at ata0-master BIOSPIO
ad1: 156334MB <Maxtor 6Y160L0 YAR41VW0> at ata0-slave BIOSPIO
acd0: CDRW <SONY CD-RW CRX140E/1.2a> at ata1-master BIOSPIO

root at kg-g4# sysctl hw.ata
hw.ata.ata_dma: 1
hw.ata.atapi_dma: 1
hw.ata.wc: 1

It seems that DMA is enabled, but the drives still reports as BIOSPIO?
I even tried with atacontrol:
root at kg-g4# atacontrol list
ATA channel 0:
    Master:  ad0 <IC35L060AVER07-0/ER6OA44A> ATA/ATAPI revision 5
    Slave:   ad1 <Maxtor 6Y160L0/YAR41VW0> ATA/ATAPI revision 7
ATA channel 1:
    Master: acd0 <SONY CD-RW CRX140E/1.2a> ATA/ATAPI revision 0
    Slave:       no device present
ATA channel 2:
    Master:      no device present
    Slave:       no device present
root at kg-g4# atacontrol info ata0
Master:  ad0 <IC35L060AVER07-0/ER6OA44A> ATA/ATAPI revision 5
Slave:   ad1 <Maxtor 6Y160L0/YAR41VW0> ATA/ATAPI revision 7
root at kg-g4# atacontrol mode ad1 UDMA5
current mode = BIOSPIO
root at kg-g4# atacontrol mode ad1 UDMA100
current mode = BIOSPIO
root at kg-g4# atacontrol mode ad0 UDMA100
current mode = BIOSPIO
root at kg-g4# atacontrol mode ad0 UDMA5
current mode = BIOSPIO

I have searched the 'net, but haven't turned up anything useful so far.
-- 
Regards,
Torfinn Ingolfsen,
Norway