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Examining the soundon.log file

If there is a problem occuring with the open sound system, it is possible that diagnostic information has been written to the system log files that may help to troubleshoot the cause.

Sample log file data

Here is some sample data taken from the /var/log/soundon.log file of a non-working (Kernel486) system:

Kernel vermagic: preempt mod_unload 486 4KSTACKS
OSS    vermagic: preempt mod_unload 486 4KSTACKS

*** Loading OSS kernel modules ***

osscore module loaded OK
Loading module oss_solo failed - ignored

*** Finished loading OSS kernel modules ***

opendir: No such file or directory
SNDCTL_MIXERINFO: No such device or address
0 audio devices
1 mixer devices
+++ ossinfo -v3 +++
Version info: OSS 4.1 (b 1051/200901181208) (0x00040100) GPL
Platform: Linux/i486 #1 PREEMPT Sun Dec 21 02:26:32 GMT 2008 (despina)

Number of audio devices:        0
Number of audio engines:        0
Number of mixer devices:        1

Device objects
 0: osscore0 OSS core services
 1: oss_solo0 ESS Solo-1

Mixer devices
 0: Device not available

Audio devices
+++ /dev/sndstat +++
+++ dmesg +++
Linux version (root@despina) (gcc version 4.1.2 (Gentoo 4.1.2 p1.1)) /
 #1 PREEMPT Sun Dec 21 02:26:32 GMT 2008
PAT not supported by CPU.
PAT WC disabled due to known CPU erratum.
osscore: This processor architecture is not compatible with vmix (info=-1) - Not enabled.
PCI: setting IRQ 9 as level-triggered
oss_solo 0000:00:0a.0: found PCI INT A -> IRQ 9
BUG: unable to handle kernel NULL pointer dereference at 00000060
IP: [<d8aea7d2>] :osscore:oss_install_mixer+0x262/0x370
*pde = 00000000 
Oops: 0000 [#1] PREEMPT 
Modules linked in: oss_solo(+) osscore af_packet usbcore nfs lockd sunrpc /
 smc_ultra 8390 bitrev crc32 mousedev rtc_cmos rtc_core rtc_lib psmouse pcspkr /
 evdev ali_agp agpgart ide_floppy unix

Pid: 2746, comm: modprobe Not tainted ( #1)
EIP: 0060:[<d8aea7d2>] EFLAGS: 00010202 CPU: 0
EIP is at oss_install_mixer+0x262/0x370 [osscore]


In the above example, we can see PAT not supported by CPU. PAT WC disabled due to known CPU erratum. It turns out in this instance that there is a PAT related bug in the kernel, which is causing the segmentation fault.

We can eliminate this fault by rebuilding the kernel with the following options:

MTRR (Memory Type Range Register) support (MTRR) [Y/n/?] n
x86 PAT support (X86_PAT) [N/y/?] n