[mythtv] backend crash on dvb channel change, backtrace included

Ben de Luca (bedel) bend at bedel.mine.nu
Tue May 4 07:30:55 EDT 2004


I have a segfault in mythback end when using dvb too

ive just managed to snag a core file and i have this from the backtrace

#0  0x403a8ba6 in send_ipack (p=0x8158e18) at  
dvbdev/transform.c:20462046                    p->buf[7] = 0x00;
#1  0x403a8fca in write_ipack (p=0x8158e18,     data=0x80ec5ca  
"n??m??}??~9?\235??m??mv?\215??nv?\235??my?~6?m??m??\215?\006\f(??? 
4\022?\235]?K??\n???\e\b.?0j\215\"rBQ0??\232?Z?i?Xl?G?\\\205Z?\203l? 
\036?)\032?\204\006\fl`p?  
Z?\031\r!??&iX?н\207\225??\212??%\227\211\024???i?\203[??\2236\005t?5? 
k`?V?T", count=166) at dvbdev/transform.c:21232123    {
#2  0x403a8ff4 in write_ipack (p=0x8158e18,     data=0x80ec5ca  
"n??m??}??~9?\235??m??mv?\215??nv?\235??my?~6?m??m??\215?\006\f(??? 
4\022?\235]?K??\n???\e\b.?0j\215\"rBQ0??\232?Z?i?Xl?G?\\\205Z?\203l? 
\036?)\032?\204\006\fl`p?  
Z?\031\r!??&iX?н\207\225??\212??%\227\211\024???i?\203[??\2236\005t?5? 
k`?V?T", count=166) at dvbdev/transform.c:21252125            int l;


 >#2 looks like it just repeats for a long ways.
does this help ?


On 04/05/2004, at 9:08 PM, Tuomas Jormola wrote:

>
> On 3.5.2004, at 12:46, Brian May wrote:
>>
>> I get the impression I may be dealing with multiple problems here, it
>> doesn't make it easy to debug. Some problems are specific to the
> Yes, I reported about weird DVB problems on the mythtv-users list but  
> received no replies. mythbackend doesn't segfault here as in Juha's  
> case but problems exist when changing channels nevertheless.
>
> Begin forwarded message:
>
>> From: Tuomas Jormola <tjormola at cc.hut.fi>
>> Date: 26. huhtikuuta 2004 21:22:27 GMT+03:00
>> To: mythtv-users at mythtv.org
>> Subject: [mythtv-users] DVB-C and hangs when changing channels
>> Reply-To: tjormola at cc.hut.fi, Discussion about mythtv  
>> <mythtv-users at mythtv.org>
>>
>> Hello,
>>
>> I live in a dorm with small cable network covering the campus area.  
>> I'm using
>> MythTV from current CVS and Technotrend DVB-C 2.1 card with stock  
>> kernel 2.6.5
>> drivers. I don't know if it's the network or my system but sometimes  
>> changing
>> channels fails. The backend just hangs with these log entries (running
>> mythbackend -v all).
>>
>> 2004-04-26 20:40:26 DVB#0 Trying to tune to channel 14.
>> 2004-04-26 20:40:26 DVB#0 Frequency: 290000000 Symbol Rate: 7146000.  
>> Inv:Auto Fec:None Mod:64
>> 2004-04-26 20:40:27 DVB#0 Waiting for frontend event after tune.
>> 2004-04-26 20:40:27 DVB#0 WARNING - Status: NO LOCK!
>> 2004-04-26 20:40:27 DVB#0 Status: CARRIER | VITERBI | SIGNAL | SYNC |  
>> LOCK.
>> 2004-04-26 20:40:27 DVB#0 Successfully tuned to channel 14.
>> 2004-04-26 20:40:27 2       ok
>> 2004-04-26 20:40:27 DVB#0 Adding pid 644, type 0
>> 2004-04-26 20:40:27 DVB#0 Adding pid 513, type 1
>> 2004-04-26 20:40:27 16      1[]:[]1021313024
>> 2004-04-26 20:40:27 121     World Business Report[]:[] []:[] []:[]  
>> []:[]200...
>> 2004-04-26 20:40:27 7       0[]:[]0
>> 2004-04-26 20:40:27 DVB#0 Adding pid 1001, type 2
>> 2004-04-26 20:40:28 DVB#0 WARNING - Uncorrectable error in packet,  
>> dropped.
>> 2004-04-26 20:40:28 DVB#0 WARNING - Uncorrectable error in packet,  
>> dropped.
>> 2004-04-26 20:40:29 DVB#0 WARNING - No data from card in 1 second.
>> 2004-04-26 20:40:29 DVB#0 WARNING - Uncorrectable error in packet,  
>> dropped.
>> 2004-04-26 20:40:29 DVB#0 WARNING - Uncorrectable error in packet,  
>> dropped.
>> 2004-04-26 20:40:30 DVB#0 WARNING - No data from card in 1 second.
>> 2004-04-26 20:40:31 DVB#0 WARNING - Uncorrectable error in packet,  
>> dropped.
>> 2004-04-26 20:40:31 DVB#0 WARNING - Uncorrectable error in packet,  
>> dropped.
>> 2004-04-26 20:40:32 DVB#0 WARNING - Uncorrectable error in packet,  
>> dropped.
>> 2004-04-26 20:40:32 DVB#0 WARNING - Uncorrectable error in packet,  
>> dropped.
>> 2004-04-26 20:40:32 DVB#0 WARNING - Uncorrectable error in packet,  
>> dropped.
>> 2004-04-26 20:40:33 DVB#0 WARNING - Uncorrectable error in packet,  
>> dropped.
>> 2004-04-26 20:40:34 DVB#0 WARNING - Uncorrectable error in packet,  
>> dropped.
>> 2004-04-26 20:40:34 DVB#0 WARNING - Uncorrectable error in packet,  
>> dropped.
>> 2004-04-26 20:40:34 DVB#0 WARNING - Uncorrectable error in packet,  
>> dropped.
>> 2004-04-26 20:40:35 DVB#0 WARNING - No data from card in 1 second.
>> 2004-04-26 20:40:36 DVB#0 WARNING - Uncorrectable error in packet,  
>> dropped.
>> 2004-04-26 20:40:36 DVB#0 WARNING - Uncorrectable error in packet,  
>> dropped.
>> 2004-04-26 20:40:36 DVB#0 WARNING - Uncorrectable error in packet,  
>> dropped.
>> 2004-04-26 20:40:37 DVB#0 WARNING - Uncorrectable error in packet,  
>> dropped.
>> 2004-04-26 20:40:37 DVB#0 WARNING - Uncorrectable error in packet,  
>> dropped.
>> 2004-04-26 20:40:38 DVB#0 WARNING - Uncorrectable error in packet,  
>> dropped.
>> 2004-04-26 20:40:38 DVB#0 WARNING - Uncorrectable error in packet,  
>> dropped.
>> 2004-04-26 20:40:39 DVB#0 WARNING - No data from card in 1 second.
>> 2004-04-26 20:40:40 DVB#0 WARNING - Uncorrectable error in packet,  
>> dropped.
>> 2004-04-26 20:40:41 DVB#0 WARNING - No data from card in 1 second.
>> 2004-04-26 20:40:41 DVB#0 WARNING - Uncorrectable error in packet,  
>> dropped.
>> 2004-04-26 20:40:41 DVB#0 WARNING - Uncorrectable error in packet,  
>> dropped.
>> 2004-04-26 20:40:42 Couldn't read data from the capture card in 15  
>> seconds.  Game over, man.
>> 2004-04-26 20:40:42 1       0
>> 2004-04-26 20:40:42 1       0
>> 2004-04-26 20:40:42 1       0
>> 2004-04-26 20:40:42 DVB#0 WARNING - Uncorrectable error in packet,  
>> dropped.
>> 2004-04-26 20:40:42 1       0
>> 2004-04-26 20:40:42 1       0
>> 2004-04-26 20:40:42 DVB#0 WARNING - Uncorrectable error in packet,  
>> dropped.
>> 2004-04-26 20:40:43 1       0
>> 2004-04-26 20:40:43 DVB#0 WARNING - Uncorrectable error in packet,  
>> dropped.
>> 2004-04-26 20:40:43 DVB#0 WARNING - Uncorrectable error in packet,  
>> dropped.
>> 2004-04-26 20:40:43 1       0
>> 2004-04-26 20:40:43 DVB#0 WARNING - Uncorrectable error in packet,  
>> dropped.
>> 2004-04-26 20:40:43 1       0
>> 2004-04-26 20:40:43 1       0
>> 2004-04-26 20:40:43 DVB#0 WARNING - Uncorrectable error in packet,  
>> dropped.
>> 2004-04-26 20:40:43 1       0
>> 2004-04-26 20:40:44 1       0
>> 2004-04-26 20:40:44 1       0
>> 2004-04-26 20:40:44 1       0
>> 2004-04-26 20:40:44 1       0
>> 2004-04-26 20:40:44 DVB#0 WARNING - No data from card in 1 second.
>> 2004-04-26 20:40:44 1       0
>> 2004-04-26 20:40:45 1       0
>> 2004-04-26 20:40:45 1       0
>> 2004-04-26 20:40:45 1       0
>> 2004-04-26 20:40:45 1       0
>> 2004-04-26 20:40:45 DVB#0 WARNING - No data from card in 1 second.
>> 2004-04-26 20:40:45 DVB#0 WARNING - Uncorrectable error in packet,  
>> dropped.
>> 2004-04-26 20:40:45 1       0
>> 2004-04-26 20:40:46 DVB#0 WARNING - Uncorrectable error in packet,  
>> dropped.
>> 2004-04-26 20:40:46 1       0
>> 2004-04-26 20:40:46 DVB#0 WARNING - Uncorrectable error in packet,  
>> dropped.
>>
>> This happens with about 5-10% of channel changes. It just repeats the  
>> last log
>> entries forever so it requires restarting both backend and frontend  
>> in order to
>> recover, which is pretty irritating in the long run. It happens with  
>> all
>> channels that are available in the network. But when a stream is  
>> flowing, it's
>> never interrupted and picture is great etc. so it's stable when you  
>> get it
>> running. Problem only exists immediatelly after a channel change. Any  
>> ideas
>> what could be wrong? Or any hints if there're some timing settings or  
>> something
>> that I might try to tune in the source code and check if it helps  
>> (I'm not
>> afraid to hack and debug things, it's just that I don't have any  
>> previous
>> experience with MythTV codebase and DVB(-C) technology :)
>>
>> Thanks,
>>
>> -- 
>> Tuomas Jormola <tjormola at cc.hut.fi>
>> _______________________________________________
>> mythtv-users mailing list
>> mythtv-users at mythtv.org
>> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
>>
>
>
> -- 
> Tuomas Jormola <tjormola at cc.hut.fi>
>
> _______________________________________________
> mythtv-dev mailing list
> mythtv-dev at mythtv.org
> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-dev
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