[linux-dvb] AverMedia 771-T, no data for 1 second, permanent signal loss

[Nathan Hand]

I've been having recent troubles with an AverMedia 771-T. The problem
started after upgrading from Myth 0.16 to Myth 0.17, using the kernel
2.6.6 for both. I have since tried upgrading the kernel to 2.6.11-rc4
but with no improvement. Downgrading to Myth 0.16 isn't desirable.

The fault is the occasional lockup of the card with this error in the
logs...

  2005-03-02 11:25:23.568 DVB#0 WARNING - No data from card in 1 second.
  2005-03-02 11:25:24.572 DVB#0 WARNING - No data from card in 1 second.
  2005-03-02 11:25:25.577 DVB#0 WARNING - No data from card in 1 second.
  2005-03-02 11:25:26.582 DVB#0 WARNING - No data from card in 1 second.

This happens during a recording, not during initial tuning. It is also
sometimes accompanied by these dmesgs. 

  bt878(0): irq FBUS risc_pc=17d9f010

But I've seen the "No data from card" without those dmesgs, so it might
not be related. Sometimes I see this message immediately preceding...

  DVB#0 WARNING - Transport Stream Continuity Error. PID = 512
  DVB#0 PID 512 _continuity_count 12 cc 3
  DVB#0 WARNING - Transport Stream Continuity Error. PID = 660
  DVB#0 PID 660 _continuity_count 12 cc 13
  DVB#0 WARNING - Transport Stream Continuity Error. PID = 650
  DVB#0 PID 650 _continuity_count 7 cc 14

Unloading and reloading the frontend (mt352) seems to fix the fault but
understandably this is a pain.

The signal is admittedly a bit weak, but I do get lock, though note the
oddity with "SBS DIGITAL 1".

root at stoli:~/.tzap# tzap "7 Digital 1"
using '/dev/dvb/adapter0/frontend0' and '/dev/dvb/adapter0/demux0'
tuning to 177500000 Hz
video pid 0x0301, audio pid 0x0302
status 00 | signal 0e83 | snr 0000 | ber 00000000 | unc 00000000 |
status 1f | signal 0e83 | snr d0d0 | ber 00000000 | unc 00000000 | FE_HAS_LOCK
status 1f | signal 0e83 | snr d2d2 | ber 00000000 | unc 00000000 | FE_HAS_LOCK
status 1f | signal 0e83 | snr d2d2 | ber 00000000 | unc 00000000 | FE_HAS_LOCK

root at stoli:~/.tzap# tzap "SBS DIGITAL 1"
using '/dev/dvb/adapter0/frontend0' and '/dev/dvb/adapter0/demux0'
tuning to 536500000 Hz
video pid 0x00a1, audio pid 0x0051
status 1f | signal 0e83 | snr d2d2 | ber 00000000 | unc 00000000 | FE_HAS_LOCK
status 01 | signal 0e83 | snr 0000 | ber 00000000 | unc 00000000 |
status 01 | signal 0e83 | snr 0000 | ber 00000000 | unc 00000000 |
status 01 | signal 0e83 | snr 0000 | ber 00000000 | unc 00000000 |

root at stoli:~/.tzap# tzap "TEN Digital"
using '/dev/dvb/adapter0/frontend0' and '/dev/dvb/adapter0/demux0'
tuning to 219500000 Hz
video pid 0x0200, audio pid 0x028a
status 00 | signal 0dc3 | snr 0000 | ber 00000000 | unc 00000000 |
status 1f | signal 0dc3 | snr cece | ber 00000000 | unc 00000000 | FE_HAS_LOCK
status 1f | signal 0dc3 | snr d1d1 | ber 00000000 | unc 00000000 | FE_HAS_LOCK
status 1f | signal 0dc3 | snr cece | ber 00000000 | unc 00000000 | FE_HAS_LOCK

Is it possible that the lockups are simply the result of a weak signal?
I already have a roof antenna.

-- 
Nathan Hand <nathanh at manu.com.au>