[asterisk-bugs] [DAHDI-linux 0013930]: dahdi_dummy does not tick on some systems

[Asterisk Bug Tracker]

The following issue is now READY FOR TESTING. 
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http://bugs.digium.com/view.php?id=13930 
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Reported By:                tzafrir
Assigned To:                sruffell
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Project:                    DAHDI-linux
Issue ID:                   13930
Category:                   dahdi_dummy
Reproducibility:            sometimes
Severity:                   minor
Priority:                   normal
Status:                     ready for testing
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Date Submitted:             2008-11-19 08:34 CST
Last Modified:              2009-03-27 18:58 CDT
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Summary:                    dahdi_dummy does not tick on some systems
Description: 
On some systems dahdi_dummy (or ztdummy, in the case of Zaptel) fails to
"tick" DAHDI and hence DAHDI does not provide a working timing source.

Indications that DAHDI (Zaptel) provides no timing source:

1. dahdi_test (zttest) does not give an error on startup, but hangs.
2. Asterisk >= 1.4.20 fails to start, and gives the ugly "no timing
source" error message:

ERROR[10981]: asterisk.c:3036 main: Asterisk has detected a problem
with your DAHDI configuration and will shutdown for your protection.
You have options:
        1. You only have to compile DAHDI support into Asterisk if you
need it.  One option is to recompile without DAHDI support.
        2. You only have to load DAHDI drivers if you want to take
advantage of DAHDI services.  One option is to unload DAHDI modules if
you don't need them.
        3. If you need DAHDI services, you must correctly configure
DAHDI.

An indication that dahdi_dummy should be the timing source for dahdi could
be:

  lsmod | grep ^dahdi
  dahdi                 231888  1 dahdi_dummy

Or to see that /proc/dahdi/1 is dahdi_dummy and is listed as "MASTER".


I have seen various suggestions on how to solve this. None seems to be a
silver bullet. 
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---------------------------------------------------------------------- 
 (0102319) sruffell (administrator) - 2009-03-27 18:58
 http://bugs.digium.com/view.php?id=13930#c102319 
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I've uploaded no_dahdi_dummy_rtc-2.patch which implements essentially what
bmd suggested.  It also completely eliminates any hint of support for the
real time clock.  On my test system, over time it even produced more
accurate results with timer test than dahdi_dummy which used the real time
clock.

Could someone running asterisk under Xen try it out? 

Issue History 
Date Modified    Username       Field                    Change               
====================================================================== 
2009-03-27 18:58 sruffell       Note Added: 0102319                          
2009-03-27 18:58 sruffell       Status                   confirmed => ready for
testing
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