Xen devel - Apr 2006 - Difficulties inserting external modules in dom0 & using a serial port

Hello Xen users!

I have developed a kernel module for the X10 CM19A USB home automation 
controller.  I attempted to install it under Xen 3.0 dom0 running on 
Linux 2.6.16, but received the following error upon executing a modprobe:

x10_cm19a: Unknown symbol force_evtchn_callback

I then attempted to embed my module within the kernel itself, to see if 
my makefiles were missing something.  Unfortunately, that made no 
difference.

Then, I installed another external module (spca5xx) to see if this is a 
common problem among all external modules, but that module worked fine.  
Has anyone encountered this before?

As indicated in my subject line, I have one other problem.  I need to 
use the serial port on my computer to read data from a digital 
multimeter (I wish they''d switch to USB), but can''t insert the
8250 module:

FATAL: Error inserting 8250 (...): Device or resource busy

 -- Michael



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Michael LeMay wrote:
> FATAL: Error inserting 8250 (...): Device or resource busy
Xen uses the console too, you might want to check your boot options
and the documentation.

Perhaps the busy error code refers to an IRQ (check the 8250 source
code to make sure), so you could look in /proc/interrupts and see if
anything else is using the same IRQ that the 8250 is trying to grab.

Same problem, clue about 8250 being modularized on SuSE but not other distros:
http://article.gmane.org/gmane.comp.emulators.xen.user/2504

Same problem, possible solution offered (didn''t work) and a clue about
IRQ problems:
http://article.gmane.org/gmane.comp.emulators.xen.user/4275
http://article.gmane.org/gmane.comp.emulators.xen.user/4290
http://article.gmane.org/gmane.comp.emulators.xen.user/4298

Same problem, no solution:
http://article.gmane.org/gmane.comp.emulators.xen.user/97

> x10_cm19a: Unknown symbol force_evtchn_callback
Nothing else in dmesg or syslog?

I usually solve this kind of problem by fiddling with the kernel version :-)...

Same problem, no solution:
http://article.gmane.org/gmane.comp.emulators.xen.user/10337
http://article.gmane.org/gmane.comp.emulators.xen.user/10354
http://article.gmane.org/gmane.comp.emulators.xen.user/10414

Same problem, impolite enough to crosspost to users- and devel-list, no replies:
http://article.gmane.org/gmane.comp.emulators.xen.user/9892

Same problem, no replies:
http://article.gmane.org/gmane.comp.emulators.xen.user/10543

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Thanks for the tip.  I manually edited Kconfig and .config and forced 
the serial modules to be compiled in (not modules), and now the port 
works fine.  I also forced my X10 driver into the kernel in the same 
way, but it doesn''t appear to get initialized.  I sure wish I knew what
I''m doing wrong...

Molle Bestefich wrote:
> Michael LeMay wrote:
>   
>> FATAL: Error inserting 8250 (...): Device or resource busy
>>     
>
> Xen uses the console too, you might want to check your boot options
> and the documentation.
>
> Perhaps the busy error code refers to an IRQ (check the 8250 source
> code to make sure), so you could look in /proc/interrupts and see if
> anything else is using the same IRQ that the 8250 is trying to grab.
>
> Same problem, clue about 8250 being modularized on SuSE but not other
distros:
> http://article.gmane.org/gmane.comp.emulators.xen.user/2504
>
> Same problem, possible solution offered (didn''t work) and a clue
about
> IRQ problems:
> http://article.gmane.org/gmane.comp.emulators.xen.user/4275
> http://article.gmane.org/gmane.comp.emulators.xen.user/4290
> http://article.gmane.org/gmane.comp.emulators.xen.user/4298
>
> Same problem, no solution:
> http://article.gmane.org/gmane.comp.emulators.xen.user/97
>
>
>   
>> x10_cm19a: Unknown symbol force_evtchn_callback
>>     
>
> Nothing else in dmesg or syslog?
>
> I usually solve this kind of problem by fiddling with the kernel version
:-)...
>
> Same problem, no solution:
> http://article.gmane.org/gmane.comp.emulators.xen.user/10337
> http://article.gmane.org/gmane.comp.emulators.xen.user/10354
> http://article.gmane.org/gmane.comp.emulators.xen.user/10414
>
> Same problem, impolite enough to crosspost to users- and devel-list, no
replies:
> http://article.gmane.org/gmane.comp.emulators.xen.user/9892
>
> Same problem, no replies:
> http://article.gmane.org/gmane.comp.emulators.xen.user/10543
>
> _______________________________________________
> Xen-users mailing list
> Xen-users@lists.xensource.com
> http://lists.xensource.com/xen-users
>   



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Xen-users@lists.xensource.com
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As an update, I figured out the "force_evtchn_callback" problem.  My 
module used the spin_lock_irq and spin_unlock_irq routines, which 
eventually trickled back to force_evtchn_callback.  I''m cross-posting 
this to -devel in case this is a real problem.  It seems like these 
calls should be supported...  Thanks for the help!

Molle Bestefich wrote:
> Michael LeMay wrote:
>   
>> FATAL: Error inserting 8250 (...): Device or resource busy
>>     
>
> Xen uses the console too, you might want to check your boot options
> and the documentation.
>
> Perhaps the busy error code refers to an IRQ (check the 8250 source
> code to make sure), so you could look in /proc/interrupts and see if
> anything else is using the same IRQ that the 8250 is trying to grab.
>
> Same problem, clue about 8250 being modularized on SuSE but not other
distros:
> http://article.gmane.org/gmane.comp.emulators.xen.user/2504
>
> Same problem, possible solution offered (didn''t work) and a clue
about
> IRQ problems:
> http://article.gmane.org/gmane.comp.emulators.xen.user/4275
> http://article.gmane.org/gmane.comp.emulators.xen.user/4290
> http://article.gmane.org/gmane.comp.emulators.xen.user/4298
>
> Same problem, no solution:
> http://article.gmane.org/gmane.comp.emulators.xen.user/97
>
>
>   
>> x10_cm19a: Unknown symbol force_evtchn_callback
>>     
>
> Nothing else in dmesg or syslog?
>
> I usually solve this kind of problem by fiddling with the kernel version
:-)...
>
> Same problem, no solution:
> http://article.gmane.org/gmane.comp.emulators.xen.user/10337
> http://article.gmane.org/gmane.comp.emulators.xen.user/10354
> http://article.gmane.org/gmane.comp.emulators.xen.user/10414
>
> Same problem, impolite enough to crosspost to users- and devel-list, no
replies:
> http://article.gmane.org/gmane.comp.emulators.xen.user/9892
>
> Same problem, no replies:
> http://article.gmane.org/gmane.comp.emulators.xen.user/10543
>
> _______________________________________________
> Xen-users mailing list
> Xen-users@lists.xensource.com
> http://lists.xensource.com/xen-users
>   



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Xen-users@lists.xensource.com
http://lists.xensource.com/xen-users

Michael LeMay wrote:
> As an update, I figured out the "force_evtchn_callback" problem.
> My module used the spin_lock_irq and spin_unlock_irq routines,
No clue whether it''s a bug that they''re not supported, but
I''d suspect a bug in Xen on account of 8250 not working when
it''s
loaded as a module?
> Thanks for the help!
Cool that you got it working :-).
Consider adding to
http://wiki.xensource.com/xenwiki/CoolConfigurations if you''re doing
something really fancy with Xen ;-)..

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