kern/112119: system hangs when starts k3b on RELENG_6

Ganbold ganbold at
Fri Apr 27 02:04:39 UTC 2007

Thomas Quinot wrote:
> * Ganbold, 2007-04-25 :
>>> Description:
>> With atapi-cam.c (rev when running k3b application, system
>> completely hangs on k3b splash screen and I had to use power button only
>> to restart the machine.
> Extremely strange. I can't offer any definite solution at this point,
> since I have no idea how this change could cause a system to hang. Here
> are a few possible investigation ideas:
> * AFAIK k3b is just a front-end for command-line tools. You should
>   determine what exact commands are spawned by k3b to identify which of
>   these is causing the apparent hang;
> * it would also be useful to enable CAM debugging options (see
>   "man 4 cam", option CAMDEBUG, and flags CAM_DEBUG_TRACE and
>   CAM_DEBUG_SUBTRACE) and to capture all console output up to the hang
>   (for example using a serial console)
> * if Scott's hunch of an interrupt storm is correct, then this issue
>   might be related to the DMA problem described under PR 103602, so
>   it would be useful to try the last patch I sent on that PR:
> * if all else fails, please let me know if the attached patch, which
>   reverts part of rev., changes anything.

I will try 
patch later today
and let you know.



> Thomas.

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