[linux-dvb] Overflows with TechnoTrend DVB-C Budget card

Tomi Orava tomimo+linux-dvb at ncircle.nullnet.fi
Sun Apr 9 13:14:20 CEST 2006


I've had some data stream continuity problems with my two
TechnoTrend DVB-C (SAA7146) cards. After enabling a couple
of kernel driver debug options (dvb_core, debug=1) I noticed
that if I run dvbstream -o 8192 >/dev/null I get the following
error's time after time:

Apr  7 12:45:04 valen kernel: function : dvb_dvr_poll
Apr  7 12:45:04 valen last message repeated 5438 times
Apr  7 12:45:04 valen kernel: dmxdev: buffer overflow
Apr  7 12:45:04 valen kernel: function : dvb_dvr_poll
Apr  7 12:45:05 valen last message repeated 15797 times

The driver doesn't emit the overflow message when running
the current version of MythTV 0.19, but on the other hand,
all the recorded streams seem to have errors in them:

[mpeg2video @ 0x30fa14c]00 motion_type at 4 15
[mpeg2video @ 0x30fa14c]00 motion_type at 0 16
[mpeg2video @ 0x30fa14c]00 motion_type at 0 17
[mpeg2video @ 0x30fa14c]mb incr damaged
[mpeg2video @ 0x30fa14c]ac-tex damaged at 24 19
[mpeg2video @ 0x30fa14c]00 motion_type at 4 20
[mpeg2video @ 0x30fa14c]invalid mb type in B Frame at 26 21
[mpeg2video @ 0x30fa14c]invalid cbp at 0 22
[mpeg2video @ 0x30fa14c]invalid cbp at 1 24
[mpeg2video @ 0x30fa14c]00 motion_type at 5 25

My hardware setup is:

Asus A7V880 / Via KT880 / Athlon XP 2800
Nvidia 5700
Seagate 7200.7 x 2 (VIA 8237, sata)
TechnoTrend DVB-C Budget (WinTV Nova-C)

(Fedora Core 5 / 2.6.16-1.2080 kernel)

I have tested with different graphics card and
as the dvbstream command is not writing to the
disk at all, I'm wondering if the problem is related to
kernel driver somehow.

BTW. I've patched by current kernel with the budget-buffer patch
        posted a couple of weeks ago on this list, but it doesn't
        seem to help in this case.

Any suggestions / ideas ?

Tomi Orava

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