>                               But then I noticed data corruption while
> running a GENERIC kernel - and found the following in the GENERIC
> config file:
> 
> ## Disable UDMA 4 which causes data corruption on the Acer Labs
> ## chipset on Sun Blade 100 and Netra X1 machines.
> wd*     at atabus? drive ? flags 0x0000
> 
> However, IIRC downgrading to UDMA3 did not fix the problems either,

I've been running a Blade 100 for a while (currently 4.0_BETA) with:

  # Disable UDMA 5 & 6 for disks
  wd0     at atabus0 drive 0 flags 0x0c00
  wd1     at atabus1 drive 0 flags 0x0c00
  # Disable UDMA and DMA for CD
  cd0     at atapibus0 drive 1 flags 0x0ff0       # ATAPI CD-ROM drives

The controller/drives attach as:

  aceride0 at pci0 dev 13 function 0
  aceride0: Acer Labs M5229 UDMA IDE Controller (rev. 0xc3)
  aceride0: bus-master DMA support present
  aceride0: primary channel configured to native-PCI mode
  aceride0: using ivec 180c for native-PCI interrupt

  cd0 at atapibus0 drive 1: <LTN486S, , Y3S2> cdrom removable
  cd0: drive supports PIO mode 4, DMA mode 2, Ultra-DMA mode 2 (Ultra/33)
  wd0 at atabus0 drive 0: <HDS728080PLAT20>
  wd0: drive supports 16-sector PIO transfers, LBA48 addressing
  wd0: 78533 MB, 159560 cyl, 16 head, 63 sec, 512 bytes/sect x 160836480 sectors
  wd0: drive supports PIO mode 4, DMA mode 2, Ultra-DMA mode 6 (Ultra/133)
  wd0(aceride0:0:0): using PIO mode 4, Ultra-DMA mode 4 (Ultra/66) (using DMA)
  cd0(aceride0:0:1): using PIO mode 4

  aceride0: secondary channel configured to native-PCI mode

  wd1 at atabus1 drive 0: <HDS728080PLAT20>
  wd1: drive supports 16-sector PIO transfers, LBA48 addressing
  wd1: 78533 MB, 159560 cyl, 16 head, 63 sec, 512 bytes/sect x 160836480 sectors
  wd1: drive supports PIO mode 4, DMA mode 2, Ultra-DMA mode 6 (Ultra/133)
  wd1(aceride0:1:0): using PIO mode 4, Ultra-DMA mode 2 (Ultra/33) (using DMA)

  raid0: RAID Level 1
  raid0: Components: /dev/wd0a /dev/wd1a
  raid0: Total Sectors: 160836352 (78533 MB)

I've not seen any data corruption problems.  I did have the hard drives
running faster, but ended up with too many:

  wd1a: DMA error writing fsbn ...
  wd1: soft error (corrected)

messages.  I need to try them with 80-wire cables.

I couldn't get the CD drive to work with DMA at all, so it's forced to be
PIO only.

Do you have a hard drive attached as the slave on either channel?

J

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