开启硬盘DMA的问题

xiawuming

linux #hdparm -d1 /dev/hda

/dev/hda:
setting using_dma to 1 (on)
HDIO_SET_DMA failed: Operation not permitted
using_dma    =  0 (off)

linux # hdparm -Tt /dev/hda

/dev/hda:
Timing cached reads:   2400 MB in  2.00 seconds = 1199.58 MB/sec
Timing buffered disk reads:   40 MB in  3.03 seconds =  13.21 MB/sec



linux # hdparm -i /dev/hda

/dev/hda:/sec


Model=ST360015A, FwRev=3.31, SerialNo=3KC0NBHK
Config={ HardSect NotMFM HdSw>15uSec Fixed DTR>10Mbs RotSpdTol>.5% }
RawCHS=16383/16/63, TrkSize=0, SectSize=0, ECCbytes=4
BuffType=unknown, BuffSize=2048kB, MaxMultSect=16, MultSect=16
CurCHS=16383/16/63, CurSects=16514064, LBA=yes, LBAsects=117231408
IORDY=on/off, tPIO={min:240,w/IORDY:120}, tDMA={min:120,rec:120}
PIO modes:  pio0 pio1 pio2 pio3 pio4
DMA modes:  mdma0 mdma1 mdma2
UDMA modes: udma0 udma1 udma2 udma3 udma4 *udma5
AdvancedPM=no WriteCache=enabled
Drive conforms to: ATA/ATAPI-6 T13 1410D revision 2:

* signifies the current active mode

主板是华硕K8N 芯片组nvidia3 250
编译内核的时候AMD and nVidia IDE support已经选上了
还有哪里有问题？
谢谢.