change dma mode?

[David Burgess <david@cjsr.com>]

Hey,

hdparm -I indicates that my hard drive is running in udma2 mode:


> # hdparm -I /dev/hda
> 
> /dev/hda:
> 
> ATA device, with non-removable media
>         Model Number:       TOSHIBA MK2018GAS
>         Serial Number:      52QJ1027T
>         Firmware Revision:  Q2.02 A
> Standards:
>         Supported: 5 4 3 2
>         Likely used: 6
> Configuration:
>         Logical         max     current
>         cylinders       16383   16383
>         heads           16      16
>         sectors/track   63      63
>         --
>         CHS current addressable sectors:   16514064
>         LBA    user addressable sectors:   39070080
>         device size with M = 1024*1024:       19077 MBytes
>         device size with M = 1000*1000:       20003 MBytes (20 GB)
> Capabilities:
>         LBA, IORDY(can be disabled)
>         bytes avail on r/w long: 46     Queue depth: 1
>         Standby timer values: spec'd by Standard, no device specific minimum
>         R/W multiple sector transfer: Max = 16  Current = ?
>         Advanced power management level: unknown setting (0x0080)
>         DMA: sdma0 sdma1 sdma2 mdma0 mdma1 mdma2 udma0 udma1 *udma2 udma3 udma4 udma5

dmesg and hdparm -t confirm this:

> # dmesg | grep hda
> Kernel command line: root=/dev/hda1 ro
>     ide0: BM-DMA at 0xff00-0xff07, BIOS settings: hda:DMA, hdb:DMA
> hda: TOSHIBA MK2018GAS, ATA DISK drive
> hda: max request size: 128KiB
> hda: 39070080 sectors (20003 MB), CHS=38760/16/63, UDMA(33)
>  hda: hda1 hda2 hda3 hda4
> 
> 
> # hdparm -t /dev/hda
> 
> /dev/hda:
>  Timing buffered disk reads:   66 MB in  3.07 seconds =  21.47 MB/sec

hdparm -I also indicates that this drive is capable of udma5, but I
can't seem to get it to use this mode. Ideas?

Thanks,
dB