[mythtv-users] Channel scan does not work

[Andrew Junev]

Friday, November 21, 2008, 3:42:19 PM, you wrote:




> -----Andrew Junev: -----
>>Hello All,
>>
>>I was using MythTV with two DVB-S tuners for quite some time now.
>>Today I tried to scan for new channels and ... it didn't work. I ran
>>mythtvsetup, went to Channel Editor, selected Transponder Scan
>>(tuned), put the data of a transponder and then clicked Next - the
>>mythtvsetup window just closed. In the terminal output I see the
>>following error:
>>
>>Connected to database 'mythconverg' at host: localhost
>>mythtvsetup: xcb_lock.c:77: _XGetXCBBuffer: Assertion `((int)
>>((xcb_req) - (dpy->request)) >= 0)' failed.
>>Aborted
>>
>>
>>I tried it with different transponders, different tuners - all the
>>time it was the same. Here's some info about my system:
>>
>># uname -a
>>Linux mythbackend 2.6.26.6-49.fc8 #1 SMP Fri Oct 17 15:59:36 EDT 2008
>>i686 i686 i386 GNU/Linux
>># mythbackend --version
>>Please include all output in bug reports.
>>MythTV Version   : 18753M
>>MythTV Branch    : branches/release-0-21-fixes
>>Library API      : 0.21.20080304-1
>>Network Protocol : 40
>>Options compiled in:
>> linux release using_oss using_alsa using_arts using_jack
>>using_backend using_dbox2 using_dvb using_firewire using_frontend
>>using_hdhomerun using_iptv using_ivtv using_joystick_menu
>>using_libfftw3 using_lirc using_opengl_vsync using_opengl_video
>>using_v4l using_x11 using_xrandr using_xv using_xvmc using_xvmcw
>>using_xvmc_vld using_glx_proc_addr_arb using_bindings_perl
>>using_bindings_python using_opengl using_ffmpeg_threads
>>using_libavc_5_3 using_live
>>
>>
>>I seem to have the latest mythtv version availble in the
>>repositories.
>>Any ideas on what the problem might be?
>>
>>--
>>Best regards,
>> Andrew

> What kind of CPU are you running this on?
> There is an issue with mythtvsetup and hyperthreaded or multi-core CPUs.
> If you have one of these try running mythtvsetup like this: taskset -c0
> mythtvsetup.

Wow! That helped, partly!
Yes, I'm running my mythbackend on a Pentium 4 with hyperthreading.

The proper command (at least for my Fedora system) is:

taskset -c 0 mythtvsetup

This way channel scan worked as usual, at first. But then, while
scanning a transponder with lots of channels (radio stations), my
mythtvsetup crashed with the same error again.

Perhaps it's not a 100% fix (as mythtvsetup may still crash), but it
helped me to add the missing channels.

Thank you very much!!!


-- 
Best regards,
 Andrew