Re: db3 access hangs OpenBSD 2.9

[Heikki Korpela <heko@iki.fi>]

On Tue, 31 Jul 2001, Craig J Copi wrote:

> Stopped at _Debugger+0x4: movl   %ebp,%esp
> ddb> trace
>        [ kbd stuff skipped ]
> --- interrupt ---
> _idle(0,ffffffff,e0664ef8,46908,e8cd609c) at _idle+0x13
> bpendtsleep(e02b0acc,28,e0153153,0) at bpendtsleep
> _sched_sync(e8cc03a8,0,0,0,0) at _sched_sync+0x171
> _start_update(0) at _start_update+0x14
> Bad frame pointer: 0xe02dde58

You should run 'ps' too - hopefully someone else can recommend
other commands to do in ddb.

> Here is a diff -u against the 2.9 dmesg for a kernel that fails
> ----------------------------------------------------------------------
[snip]
> Not much catches my eye except the ultra-dma 2 vs 4.

I have no idea if these are related, but if you want to try with UDMA 2,
you can try downgrading it from BIOS, or forcing a specific PIO/DMA
mode with kernel config. (See wd(4)). Probably it will help developers
if you do this by taking a copy of GENERIC and only changing this
specific thing there.

Possibly someone can also suggest some _DEBUG options to help trace
this; there are hundreds of such options in the kernel source.

If this is reproducable and you can generate a trace, I suggest you
also sendbug(1) this so that it makes it into the bug tracking system.

> 	Craig

-- 
<---------------------------------------------------------------------->
          Heikki Korpela -- heko@iki.fi -- http://iki.fi/heko/