Soundon.log

From Open Sound System

[edit] 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.

[edit] 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:  2.6.27.10 preempt mod_unload 486 4KSTACKS
OSS    vermagic:  2.6.27.10 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 2.6.27.10 #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 2.6.27.10 (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 (2.6.27.10 #1)
EIP: 0060:[<d8aea7d2>] EFLAGS: 00010202 CPU: 0
EIP is at oss_install_mixer+0x262/0x370 [osscore]

[edit] Diagnosis

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