xfce4-mixer-plugin crashed with SIGSEGV in g_type_check_instance_is_a()

[BearTM]

Binary package hint: xfce4-mixer

Mythbuntu 8.04
2 sound cards (onboard CMedia CMI8738, Audigy2 PCI)
Configured for Audigy2
Crash occurred on boot (repeated twice, but not every reboot)
Panel was not accessed or opened - crash occurs without any user interaction

DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=8.04
DISTRIB_CODENAME=hardy
DISTRIB_DESCRIPTION="Ubuntu hardy (development branch)"

ProblemType: Crash
Architecture: i386
Date: Fri Mar 21 12:30:46 2008
DistroRelease: Ubuntu 8.04
ExecutablePath: /usr/lib/xfce4/panel-plugins/xfce4-mixer-plugin
NonfreeKernelModules: nvidia
Package: xfce4-mixer 1:4.4.2-2ubuntu2
PackageArchitecture: i386
ProcCmdline: /usr/lib/xfce4/panel-plugins/xfce4-mixer-plugin socket_id 31457321 name xfce4-mixer id 12054886131 display_name Volume\ Control size 24 screen_position 1
ProcEnviron:
 PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games
 LANG=en_NZ.UTF-8
 SHELL=/bin/bash
Signal: 11
SourcePackage: xfce4-mixer
StacktraceTop:
 g_type_check_instance_is_a ()
 ?? ()
 ?? ()
 ?? ()
 ?? ()
Title: xfce4-mixer-plugin crashed with SIGSEGV in g_type_check_instance_is_a()
Uname: Linux 2.6.24-12-generic i686
UserGroups: adm admin audio cdrom dialout dip floppy fuse lpadmin mythtv plugdev video

[Apport retracing service (apport)]

StacktraceTop:IA__g_type_register_dynamic (parent_type=1016, type_name=0x80aee38 "\020x\t\b",
?? ()
?? ()
?? ()
?? ()

[BearTM (beartm)]

After many days of frustration with this machine, I now believe that this crash is principally due to hardware/configuration failure instead of software, and this bug report should potentially be closed off.

The Motherboard BIOS settings were somehow corrupted and changed without my actually doing this, and this appeared to occur randomly on reboot. In the latest instance, not only was the CPU underclocked (bad Memory Bus timings - 100Mhz instead of 200Mhz), but the PCI Bus timing was set to Manual, and was overclocked to 75Mhz instead of the default 66Mhz. If this was the case during the above faults, it would definitely lead to issues with valid data availability on the PCI bus, and could lead to other lockup issues, which, while they are reproducible, are not due to application software. The probable effect was that the AGP Video card (nVidia) could cope with the faster bus, but the sound card was entirely unable to and caused the fault.

Replacing the CMOS Battery, cleaning and rebuilding the machine, and reconfiguring the BIOS correctly to proper defaults has now "solved" this problem. The machine does not exhibit this failure anymore, without any software changes made, other than applying the most recent 8.04 updates. Very strange that the CMOS checksum did not fail in any of these conditions ... so I'm not entirely sure what or why this was happening, and/or if there is a fault in the BIOS itself. Will research further independently.