[Mplayer-dvb] Reproducible MPlayer Crash with dvb-t card

[Nico Sabbi]

David Maslen wrote:

>Hi All,
>
>I think I need a bit of help to know how to report this bug. ie Strace
>or other tools.
>
>It may not exactly be a mplayer bug, but I can reproduce it with
>mplayer and not with any other program on my system.
>
>I have a Avermedia DVB-T card. It's working on my debian system with a
>V2.6.5 kernel. The system is a Celeron 1400, with aprox 380M SDRAM, on
>an older Asus P2B-F motherboard.
>
>Below is a cut and paste from a screen session.  It shows me dumping a
>stream to disk. It starts to save. Then I jump to another shell (via
>the network) and run a disk intensive command like find /
>
>  
>

the error you see below is due to the fact that mplayer didn't read() 
fast enough from the
DVB drivers, which overflew.
This is logical if  your system isn't fast enough to handle the load.

>The Mplayer session immediately ends, and won't start again until I
>reload the kernel module dvb-bt8xx. (rmmod then modprobe).
>  
>

this sounds like a bug in the dvb drivers (either bttv or dvb-bt8xx).
Does tzap -r + mplayer /dev/dvb/adapter0/dvr0  work correctly when you 
have this problem?

>I did record a show while watch another last night (at the console not
>across the network), which makes me think it might not be disk access
>or cpu load. I think it could be related to network access, as running
>a P2P file sharing application or transferring a large file across the
>network also seems to have the same effect (ie. cause a crash).
>  
>

it's not a crash: mplayer simply exists because repeated read() from the 
card failed;
you can increase this value from 5 to the value you want (priv->retry in 
libmpdemux/dvbin.c).
Maybe using your network card triggers something that raises the system 
load?
Is your disk very slow? Something in 2.6.x  seems to have a similar 
effect on my system:
every massive I/O on the disk seems to almost paralize my PC; I suspect 
anticipatory scheduling,
so I'll try to disable it.
Are you sharing interrupts?

>dmm at trinity:/opt/dm200g/video/television$ mplayer dvb://Seven
>-dumpfile test.ts -dumpstream
>MPlayer 1.0pre4-3.3.3 (C) 2000-2004 MPlayer Team
>
>CPU: Intel Celeron 2/Pentium III Tualatin 1404 MHz (Family: 6,
>Stepping: 4)
>Detected cache-line size is 32 bytes
>MMX2 supported but disabled
>SSE supported but disabled
>CPUflags:  MMX: 1 MMX2: 0 3DNow: 0 3DNow2: 0 SSE: 0 SSE2: 0
>Compiled for x86 CPU with extensions: MMX
>
>Reading config file /etc/mplayer/mplayer.conf
>Reading config file /home/dmm/.mplayer/config
>Reading /home/dmm/.mplayer/codecs.conf: 61 audio & 169 video codecs
>font: can't open file: /home/dmm/.mplayer/font/font.desc
>Font /usr/share/mplayer/font/font.desc loaded successfully! (206
>chars)
>Linux RTC init error in ioctl (rtc_irqp_set 1024): Permission denied
>Try adding "echo 1024 > /proc/sys/dev/rtc/max-user-freq" to your
>system startup scripts.
>Using usleep() timing
>Input config file /home/dmm/.mplayer/input.conf parsed: 47 binds
>Opening joystick device /dev/input/js0
>Can't open joystick device /dev/input/js0 : No such file or directory
>Can't init input joystick
>Setting up LIRC support...
>mplayer: could not connect to socket
>mplayer: Connection refused
>Failed to open LIRC support.
>You will not be able to use your remote control.
>
>Playing dvb://Seven.
>code taken from dvbstream for mplayer v0.4pre1 - (C) Dave Chapman 2001
>Released under the GPL.
>Latest version available from http://www.linuxstb.org/
>dvb_tune Freq: 177500000
>dvb_streaming_read, attempt N. 6 failed with errno 0 when reading 1944
>bytes
>dvb_streaming_read, attempt N. 5 failed with errno 0 when reading 1944
>bytes
>dvb_streaming_read, attempt N. 4 failed with errno 0 when reading 1944
>bytes
>dvb_streaming_read, attempt N. 3 failed with errno 0 when reading 1944
>bytes
>dvb_streaming_read, attempt N. 2 failed with errno 0 when reading 1944
>bytes
>dvb_streaming_read, attempt N. 1 failed with errno 0 when reading 1944
>bytes
>dvb_streaming_read, attempt N. 6 failed with errno 0 when reading 2048
>bytes
>dvb_streaming_read, attempt N. 5 failed with errno 0 when reading 2048
>bytes
>dvb_streaming_read, attempt N. 4 failed with errno 0 when reading 2048
>bytes
>dvb_streaming_read, attempt N. 3 failed with errno 0 when reading 2048
>bytes
>dvb_streaming_read, attempt N. 2 failed with errno 0 when reading 2048
>bytes
>dvb_streaming_read, attempt N. 1 failed with errno 0 when reading 2048
>bytes
>dvb_streaming_read, return 0 bytes
>Core dumped ;)
>
>Exiting... (End of file)
>dmm at trinity:/opt/dm200g/video/television$
>
>  
>
       Nico