I got this hang once in Linux and I seem to remember /proc/cpuinfo
containing a line 'L2 cache: 1024Kb' or something like that. After
that first hang, I cannot find the L2-cache line in /proc/cpuinfo any
more _and_ I did not have a single hang (apart from during rebooting).

Actually I hoped to be able to play with the l2cr values (whatever
valid values might be for this machine), but I cannot find the
corresponding /proc/sys/kernel/l2cr which should exist according to
Documentation/sysctl/kernel.txt . It might be that a smaller value
(say, 512Kb) might still work. I don't know.

Furthermore the machine feels sluggish. A kernel compile takes ~5.5
hours, while the same compile on my P4 takes ~10 minutes. But it might
be normal for a 400Mhz G3, I don't know...

Strange... it might indeed have a hw breakage.

Goolging around for 'lombard bogomips' I got the impression the value
should be 600 to 800, or at least of that order of magnitude. Since 33
is far outside this range, I thought that to be the reason. Apparently
not, then...

It used to be based on the cpu frequency but not any more.

Ok, I got further with this one thanks to you :)

Suspend-to-RAM works like a charm! However, when it wakes up the
screen is black (and I thought the suspend had crashed...). With fn-F2
(increase brightness key) I can make the screen visible again.

Ah ok, so the brightness isn't properly restored. I suppose that can be
fixed ;-)

How am I supposed to power down the machine? halt -p? With
'powerprefs' I can only select different suspend modes but not
power-down modes...

halt or shutown -h now

This leaves me to some OOPSes still:
  - removing the PCMCIA wifi card (Orinoco) while the network is up
  - booting the machine with the wifi card inserted
  - bringing up the wifi card while no access point is found

Weird...

(maybe-related:)
And a warning in dmesg which reads (no OOPS):
pcmcia: the driver needs updating to supported shared IRQ lines.
...which corresponds to /proc/interrupts :
 22:    4912397   PMAC-PIC  Level     yenta, pcmcia0.0

Could be a driver issue

The wifi-at-startup-OOPS:
pccard: PCMCIA card inserted into slot 0
cs: memory probe 0x0c0000-0x0fffff: excluding 0xc0000-0xfffff
cs: memory probe 0x60000000-0x60ffffff: excluding 0x60000000-0x60ffffff
cs: memory probe 0x80000000-0xfcffffff: excluding 0x80000000-0x81ffffff
cs: memory probe 0xfd000000-0xfdffffff:Machine check in kernel mode.
Caused by (from SRR1=49030): Transfer error ack signal
Oops: Machine check, sig: 7 [#1]
...
Call Trace:
[D30ABD40] [D5044E90] pcmcia_read_cis_mem+0x15c/0x274 [pcmcia_core] (unreliable)
[D30ABD70] [D5045110] read_cis_cache+0x168/0x16c [pcmcia_core]
[D30ABD90] [D50452B8] pccard_get_next_tuple+0x100/0x454 [pcmcia_core]
[D30ABDD0] [D50456A4] pccard_get_first_tuple+0x98/0x144 [pcmcia_core]
...

When I insert the PCMCIA card at a later stage, there are no 'cs: '
lines in dmesg at all.

So still some riddles to be solved ;)

Yeah, some weird problems with the pcmcia controller, mgiht be incorrect
resource assignments...

Ben.