Can you only set dma status on unmounted drives? (The manpages for
hdparm say nothing of this) But if so, how do you set it on your root
partition?
Why is dma disabled under 2.0.x by default in the first place?
I can set multi-word dma using -X34, but hdparam still lists dma as being
off, and pio changes seem not to be supported.
Here's some output from the various hdparm commands..
root:/usr/src/linux/drivers/block> hdparm -d1 /dev/hda
/dev/hda:
setting using_dma to 1 (on)
HDIO_SET_DMA failed: Operation not permitted
using_dma = 0 (off)
root:/root> hdparm -X34 /dev/hda
/dev/hda:
setting xfermode to 34 (multiword DMA mode2)
root:/root> hdparm -p2 /dev/hda
/dev/hda:
attempting to set PIO mode to 2
HDIO_SET_PIO_MODE failed: Function not implemented
root:/root> hdparm -c1 /dev/hda
/dev/hda:
setting 32-bit I/O support flag to 1
I/O support = 1 (32-bit)
root:/root> hdparm /dev/hda
/dev/hda:
multcount = 0 (off)
I/O support = 1 (32-bit)
unmaskirq = 0 (off)
using_dma = 0 (off)
keepsettings = 0 (off)
nowerr = 0 (off)
readonly = 0 (off)
readahead = 8 (on)
geometry = 1024/255/63, sectors = 16514064, start = 0
root:/root> hdparm -i /dev/hda
/dev/hda:
Model=QUANTUM FIREBALL SE8.4A, FwRev=API.0C00, SerialNo=33881556
Config={ HardSect NotMFM HdSw>15uSec Fixed DTR>10Mbs }
RawCHS=16383/16/63, TrkSize=32256, SectSize=512, ECCbytes=4
BuffType=3(DualPortCache), BuffSize=80kB, MaxMultSect=16, MultSect=off
DblWordIO=no, maxPIO=2(fast), DMA=yes, maxDMA=2(fast)
CurCHS=16383/16/63, CurSects=16514064, LBA=yes, LBAsects=16514064
tDMA={min:120,rec:120}, DMA modes: sword0 sword1 sword2 mword0 mword1 *mword2
IORDY=on/off, tPIO={min:120,w/IORDY:120}, PIO modes: mode3 mode4
--- Mike Perry Maintainer of www.linuxos.org and subpages.Insert funny fortune here.
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