Hello Alvin,
On Sat, 28 Dec 2002, Alvin Oga wrote:
> > > > >/dev/hda:
> > > > > setting using_dma to 1 (on)
> > > > > HDIO_SET_DMA failed: Operation not permitted
> > > > > using_dma = 0 (off)
> > > >
> > > > Do it as root
> >
> > of course
> >
> > > sometimes .. you have to make sure that the chips and
> > > the drive supports DMA ...
> > > - ( check the kernel IDE/dma options )
> >
> > I think it is the chips which don't do DMA.
> > circa 1990 hardware
>
> ah ... first problem..... those circa drives supports
> multiword dma ... not ultra-dma ....
>
> which exactly is supported...
> hdparm -iv /dev/hda will tell you
bms:~# hdparm -iv /dev/hda
/dev/hda:
multcount = 0 (off)
IO_support = 0 (default 16-bit)
unmaskirq = 0 (off)
using_dma = 0 (off)
keepsettings = 0 (off)
readonly = 0 (off)
readahead = 8 (on)
geometry = 59570/16/63, sectors = 60046560, start = 0
Model=FUJITSU MPG3307AT, FwRev=02B9, SerialNo=VG13P1201HK8
Config={ HardSect NotMFM HdSw>15uSec Fixed DTR>10Mbs }
RawCHS=16383/16/63, TrkSize=0, SectSize=0, ECCbytes=4
BuffType=DualPortCache, BuffSize=2048kB, MaxMultSect=16, MultSect=off
CurCHS=16383/16/63, CurSects=16514064, LBA=yes, LBAsects=60046560
IORDY=yes, 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=yes: disabled (255) WriteCache=enabled
Drive conforms to: ATA/ATAPI-5 T13 1321D revision 1: 1 2 3 4 5
<...>
> > hmmm...
> > # CONFIG_IDEDMA_AUTO is not set
> > # CONFIG_DMA_NONPCI is not set
>
> and if that is the kernel you're booting...
> hdparm options in the bootups will not work
# echo "..." >/proc/... could fix that?
> > I'm curious about the PIO modes, and if one of those is what is being
> > used. Since the drive is defaulting to a DMA mode but the OS isn't
> > doing DMA, is the system falling back to PIO and should explicitly
> > selecting the best PIO mode be expected to improve performance.
>
> the list of dma options from hdparm -iv wil tell you which
> one ( marked w/ * ) your machine is currently using
The drive is defaulting to mdma, which is reasonable for the
hardware... so it probably doesn't matter that hdparm fails to set
a DMA mode, or the kernel thinks DMA isn't happening, the hardware has
it all sorted out?
> > gotta lot of reading and fiddling to do
>
> pio vs udma vs dma vs ...
> http://www.Linux-1U.net/Disks/
>
> and for system fiddling and tuning
> http://www.Linux-1U.net/Tuning
Thanks
- Bruce
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