Re: Debugging driver modules

[Takashi Iwai <tiwai@suse.de>]

At 30 Nov 2002 16:27:43 -0600,
Scott Bahling wrote:
> 
> Hello-
> 
> I have a STAudio DSP24 mkII and I have noticed that recent changes(after
> NOV 13) in the CVS creates an ICE1712 driver that locks up my kernel.
> Instead of just complaining about this problem I thought I might try to
> narrow down the location in the driver that is causing the lockup.
 
can you confirm the date when the critical change was applied to cvs?
the driver before Nov. 13 works really?

if so, you can make a diff between these two versions and find out
which change causing the lock up.


> Does anyone have any tips on debugging the driver modules? Is anyone
> using a debugger to do this? I have looked at UML, but I am not sure if
> there is a way to access the sound hardware with it.

AFAIK, UML is not possible for such a low-level driver, because it
needs the direct i/o access.
other kernel debuging tools might be useful, e.g. strack-tracing via
alt-sysrq.  i cannot tell much about them since i've not used, too.

also, if the problem is a dead spinlock, you can try the kernel with 
SPINLOCK_DEBUG flag to find the culprit.


Takashi


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