apalling IDE performance on ds20

[David Monro <davidm@davidmonro.net>]

Hi,

I'm getting really slow IDE performance on my ds20.

Kernel is 2.6.8-2-generic 2.6.8-9.
Disk is a Maxtor 6Y160P0 160G.
Machine is a ds20, using the onboard CY82C693 controller:

CY82C693: chipset revision 0
CY82C693: not 100% native mode: will probe irqs later
CY82C693U driver v0.34 99-13-12 Andreas S. Krebs (akrebs@altavista.net)
    ide0: BM-DMA at 0x8400-0x8407, BIOS settings: hda:DMA, hdb:pio
PCI: Enabling device: (0000:00:05.2), cmd 7
    ide1: BM-DMA at 0x8408-0x840f, BIOS settings: hdc:DMA, hdd:DMA
hda: Maxtor 6Y160P0, ATA DISK drive
ide0 at 0x1f0-0x1f7,0x3f6 on irq 14
hda: max request size: 1024KiB
hda: 320173056 sectors (163928 MB) w/7936KiB Cache, CHS=19929/255/63, (U)DMA

hdparm shows it using dma:
hdparm /dev/hda

/dev/hda:
 multcount    =  0 (off)
 IO_support   =  0 (default 16-bit)
 unmaskirq    =  0 (off)
 using_dma    =  1 (on)
 keepsettings =  0 (off)
 readonly     =  0 (off)
 readahead    = 256 (on)
 geometry     = 19929/255/63, sectors = 320173056, start = 0

(setting the multcount to 16, the unmaskirq to on, and io_support to
32bit doesn't help).

Test results:
 hdparm -Tt /dev/hda

/dev/hda:
 Timing cached reads:   900 MB in  2.01 seconds = 448.47 MB/sec
 Timing buffered disk reads:   12 MB in  3.53 seconds =   3.40 MB/sec

I'm sure this controller and disk combination should do a little better
than that :)

Any ideas?

Cheers,

	David