NetBSD 10 on Cobalt doesn't like IDE DMA

[John Klos <john%klos.com@localhost>]

Hi, all,

NetBSD 10 is coming soon, so I figured I'd see how things are running on 
my Cobalt Raq. My Raq has been stable for years, compiling thousands of 
pkgsrc packages while having no issues.

I compiled an almost completely GENERIC (GENERIC with root at wd0e) kernel 
from today's sources...

There's one big regression: viaide0 can't do DMA. Whereas the Raq has run 
for years with no problems, with the new kernel I get a steady stream of:

[ 1370.2451615]         type: ata tc_bcount: 32768 tc_skip: 0
viaide0:0:0: bus-master DMA error: missing interrupt, status=0x20
[ 1370.2584021] wd0e: DMA error reading fsbn 922830144 of 922830144-922830207 (wd0 bn 927046976; cn 919689 tn 7 sn 23), xfer 1f88, retry 0
[ 1370.7551615] wd0: soft error (corrected) xfer 1f88

I recompiled the kernel with:

wd* 		at atabus? drive ? flags 0x0ff0

which turns off DMA, the drive configures with "wd0(viaide0:0:0): using 
PIO mode 4", and the system is happy, if just a wee bit slower.

Is anyone else testing NetBSD 10 on Cobalt hardware?

Thanks,
John