[clue-tech] Need help diagnosing weird problem

[Bruce Ediger]

I'm not even sure how to phrase this one, so please excuse the long-winded
explanation.

Hardware:
HP Pavilion mini-tower, 2.2 GHz Celeron, Intel 82xxx chipset.
Basic IDE disk, all of this vintage 2003 or so.

I've been running Arch linux on the thing, and it's worked out reasonably
well, with the exception of a frighteningly buggy "Brookdale" graphics
chipset X11 driver.  I've had to downgrade to Xorg 1.6-something, and
appropriate DRI and Mesa and OpenGL downgrades just to keep X from
freezing the display every 32 seconds.

I did a "pacman -Syu" over the weekend, and ended up rebooting on Sunday
night, because the Arch Overlords pushed a new kernel - 2.6.36-something.

The system hasn't worked correctly since.  The first few times I booted
it, X locked up, making me think that Intel  82845G/GL[Brookdale-G]/GE Chipset
Integrated Graphics Device problems had returned.

After that, booting has become progressively less reliable.  A multitude of
symptoms have happened.  I rarely get it to boot successfully.  With the
Arch kernel:

Most often: after the "Waiting for UDEV events" line in the boot, I get
a stack trace ending in "<IRQ>"

Sometimes: when the boot sequence gets to "Decompressing Linux...", it hangs.

Rarely: a kernel panic ending in "Unable to handle kernel paging request
at 4a67be00"

Once: what looked like an infinite stack trace scrolled up the screen for
a long time, before I pulled the power cord.

I have booted from a Slackware 13.1 install CD, but even that's not super
reliable.  It took 2 or 3 tries to get to the shell prompt.  e2fsck claimed
the IDE disks were fine.

I booted "memtest 4.10" from CD, and ran it for 3 passes with no errors,
based on a suggestion I found in the Arch forums.  I haven't seen anyone
else claiming to have problems since the last kernel push, so maybe it's
just this PC.

I'm puzzled.  Anybody got any ideas?  Is the CPU shot (specifically the MMU)?
Is a memory stick gone bad?  Is the disk weird?