[linux-dvb] 2 MSI Megasky 580s - different tuning results

Mandeep Gill mandeepg at gmail.com
Wed Apr 18 17:22:31 CEST 2007


Hi,

I've currently have 2 MSI Megasky 580s running as inputs to a mythtv
system. However even though they are completely identical cards
running of the same aerial in a strong signal area I get wildly
different tuning results for both cards - one of them doesn't lock
even though the signal strength is high.

I'm running an ~3 week old CVS checkout from the v4l-dvb repository,
and have patched the zarlink code to include a USB sleep delay of 15us
as described in the following mails:

http://www.linuxtv.org/pipermail/linux-dvb/2007-February/015910.html
http://linuxtv.org/pipermail/linux-dvb/2007-February/015863.html

Both cards work fine on Windows - I believe it may have something to
do with the Automatic Gain Control but can't figure it out. I've added
an i2c write to zl10535 code as described in the following mail but it
has no effect.
http://www.linuxtv.org/pipermail/linux-dvb/2007-February/015927.html

I happy to test any patches or code that people may have.

Thanks
Mandeep Gill

Output from "lsmod"
Module                  Size  Used by
dvb_usb_gl861           7108  0
dvb_usb                20364  1 dvb_usb_gl861
dvb_core               72496  1 dvb_usb
dvb_pll                13764  1 dvb_usb
zl10353                 6024  2
qt1010                  6020  2
i2c_isa                 4992  0

Output from "uname -a"
Linux bowser 2.6.20-gentoo-r3 #1 Mon Mar 19 19:13:37 GMT 2007 x86_64
AMD Sempron(tm) Processor 3200+ AuthenticAMD GNU/Linux

Output from Tzap on Tuner 0 - same aerial, locks and works fine
tzap -a 0 "BBC ONE"
using '/dev/dvb/adapter0/frontend0' and '/dev/dvb/adapter0/demux0'
reading channels from file '/root/.tzap/channels.conf'
tuning to 641833330 Hz
video pid 0x0258, audio pid 0x0259
status 00 | signal 7c2c | snr 0000 | ber 00000000 | unc 00000000 |
status 1e | signal 8200 | snr cfcf | ber 00000000 | unc 00000000 | FE_HAS_LOCK
status 1e | signal 8304 | snr cfcf | ber 00000000 | unc 00000000 | FE_HAS_LOCK
status 1e | signal 81dc | snr cfcf | ber 00000000 | unc 00000000 | FE_HAS_LOCK
status 1e | signal 820c | snr cece | ber 00000000 | unc 00000000 | FE_HAS_LOCK
status 1e | signal 81b0 | snr d2d2 | ber 00000000 | unc 00000000 | FE_HAS_LOCK

Output from Tzap on Tuner 1 - same aerial, doesn't lock
tzap -a 1 "BBC ONE"
using '/dev/dvb/adapter1/frontend0' and '/dev/dvb/adapter1/demux0'
reading channels from file '/root/.tzap/channels.conf'
tuning to 641833330 Hz
video pid 0x0258, audio pid 0x0259
status 00 | signal 76c4 | snr 0000 | ber 00000000 | unc 00000000 |
status 00 | signal 7608 | snr 0000 | ber 00000000 | unc 00000000 |
status 00 | signal 757c | snr 0000 | ber 00000000 | unc 00000000 |
status 00 | signal 75b8 | snr 0000 | ber 00000000 | unc 00000000 |
status 00 | signal 75c4 | snr 0000 | ber 00000000 | unc 00000000 |
status 00 | signal 763c | snr 0000 | ber 00000000 | unc 00000000 |
status 00 | signal 7614 | snr 0000 | ber 00000000 | unc 00000000 |



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