2.6.13rc4 hang

[Stephen Clark <stephen.clark@earthlink.net>]

Hello List,

I am having a problem 2.6.13rc4 described below on a HP Pavilion N5430 
laptop.


1) If I cold boot with only 'lacpi' to run level 3 - shortly after I get
the login prompt the laptop freezes.

2) If I cold boot with 'lacpi  acpi=off  pci=noacpi,usepirqmask'  the
system boots and does not freeze but  when I try to play sound I get no
interrupts from my sound card.

3) If I now warm boot from step  2 with only 'lacpi' my  laptop seems to
be stable  and I have sound.

I did this several times to try and really verify the above scenarios.

Diff between dmesg output from step 1 and step 3
$ diff dmesg104550 dmesg105029
43,45c43,44
< CPU: After generic identify, caps: 0183f9ff c1c7f9ff 00000000 00000000
00000000 00000000 00000000
< CPU: After vendor identify, caps: 0183f9ff c1c7f9ff 00000000 00000000
00000000 00000000 00000000
< Enabling disabled K7/SSE Support.
---
> CPU: After generic identify, caps: 0383f9ff c1c7f9ff 00000000 
00000000 00000000 00000000 00000000
> CPU: After vendor identify, caps: 0383f9ff c1c7f9ff 00000000 00000000 
00000000 00000000 00000000
55c54
< ACPI: setting ELCR to 0200 (from 0800)
---
> ACPI: setting ELCR to 0200 (from 0820)
92c91
< audit(1122734733.300:1): initialized
---
> audit(1122735011.179:1): initialized
161c160
< Detected 849.810 MHz processor.
---
> Detected 850.192 MHz processor.
163c162
< powernow: Minimum speed 299 MHz. Maximum speed 849 MHz.
---
> powernow: Minimum speed 300 MHz. Maximum speed 850 MHz.

What is the best way to debug a hang? I there a way to turn on verbose
debugging at boot? Also why would
the hardware capabilities be different between a cold boot and a warm boot?

Thanks for any advice,
Steve