asterisk users - Apr 2009 - dahdi_dummy: Unable to register DAHDI rtc driver

Hello there:

I think I have a silly kernel configuration problem. I'm running:
* vanilla 2.6.27.10 kernel built from source
* dahdi-2.1.0.4 built from source

So far so good,
dahdi module loads just fine:
dahdi: Telephony Interface Registered on major 196
dahdi: Version: 2.1.0.4

when I try to:
hal04 dahdi # modprobe dahdi_dummy
FATAL: Error inserting dahdi_dummy
(/lib/modules/2.6.27.10/dahdi/dahdi_dummy.ko): Input/output error

kernel messages gives me:
dahdi_dummy: Unable to register DAHDI rtc driver

I'm probably doing something silly here.

Then I was curious, so I backed up to a 2.6.25.9 kernel I already had,
and dahdi_dummy loaded just fine:
dahdi_dummy: RTC rate is 1024

Does anybody know whether:
* something changed in mainline kernel that breaks dahdi
* there was a new kernel parameter that I should have set differently?

No emergency, more like an observation. I'm just backing off kernel
version for now.

David Backeberg wrote:
> Hello there:
> 
> I think I have a silly kernel configuration problem. I'm running:
> * vanilla 2.6.27.10 kernel built from source
> * dahdi-2.1.0.4 built from source
> 
> So far so good,
> dahdi module loads just fine:
> dahdi: Telephony Interface Registered on major 196
> dahdi: Version: 2.1.0.4
> 
> when I try to:
> hal04 dahdi # modprobe dahdi_dummy
> FATAL: Error inserting dahdi_dummy
> (/lib/modules/2.6.27.10/dahdi/dahdi_dummy.ko): Input/output error
> 
> kernel messages gives me:
> dahdi_dummy: Unable to register DAHDI rtc driver
> 
> I'm probably doing something silly here.
> 
> Then I was curious, so I backed up to a 2.6.25.9 kernel I already had,
> and dahdi_dummy loaded just fine:
> dahdi_dummy: RTC rate is 1024
> 
> Does anybody know whether:
> * something changed in mainline kernel that breaks dahdi
> * there was a new kernel parameter that I should have set differently?
> 
There is a kernel config parameter called CONFIG_HPET_EMULATE_RTC, that 
if defined in the kernel config, will cause the behavior that you're 
seeing.  I have not looked to see at which version that option came in.

However, I think support for RTC in dahdi_dummy is best dropped.  There 
is a patch on mantis (http://bugs.digium.com/view.php?id=13930) against 
dahdi_dummy that allows it to provide accurate timing with standard 
kernel timers that you may want to try.

Cheers,
-- 
Shaun Ruffell
Digium, Inc. | Linux Kernel Developer
445 Jan Davis Drive NW - Huntsville, AL 35806 - USA
Check us out at: www.digium.com & www.asterisk.org