On Wed, Feb 07, 2001 at 04:35:25PM -0500, Curt Sampson wrote:
> On Wed, 7 Feb 2001, Manuel Bouyer wrote:
> 
> > Mode 1, isn't it ? The chipset can at best do mode 2.
> 
> Right. What I get is this:
> 
> wd0: transfer error, downgrading to Ultra-DMA mode 1
> wd0(pciide0:0:0): using PIO mode 4, Ultra-DMA mode 1 (using DMA data transfers)
> wd0a: DMA error reading fsbn 16 of 16-31 (wd0 bn 79; cn 0 tn 1 sn 16), retrying
> wd0: soft error (corrected)
> root file system type: ffs

[...]
> So it looks to me like the drive just happened to fail at the time I
> did the upgrade.

The initial downgrade of modes also happens for me on a P5A board:

wd0 at pciide0 channel 0 drive 0: <Maxtor 91531U3>
wd0: drive supports 16-sector pio transfers, lba addressing
wd0: 14655 MB, 16383 cyl, 16 head, 63 sec, 512 bytes/sect x 30015216 sectors
wd0: 32-bit data port
wd0: drive supports PIO mode 4, DMA mode 2, Ultra-DMA mode 4
pciide0: primary channel interrupting at irq 14
wd0(pciide0:0:0): using PIO mode 4, Ultra-DMA mode 2 (using DMA data transfers)


wd0: transfer error, downgrading to Ultra-DMA mode 1
wd0(pciide0:0:0): using PIO mode 4, Ultra-DMA mode 1 (using DMA data transfers)
wd0a: DMA error reading fsbn 458928 of 458928-458943 (wd0 bn 458991; cn 455 tn 5
 sn 36), retrying
wd0: soft error (corrected)

After that, it works flawlessly, though. The pciide version is:

pciide0 at pci0 dev 15 function 0: Acer Labs M5229 UDMA IDE Controller (rev. 0xc1)

I've always wondered if the chipset reports more than it actually can do,
or that there is some glitch in the driver. But it has not been a real
problem for me.

- Frank