[linux-dvb] Twinhan Starbox, get lock, but no signal strength or picture

Chris Scholz cs42 at gmx.de
Sat Oct 8 14:02:36 CEST 2005


Hello everyone,

I have been using a MythTV server with 3 Twinhan PCI DVB-S cards (2x
1020, 1x 1025) for some time. Now I wanted to replace one of them with a
Twinhan Starbox USB2.0 external DVB-S box, but I can't get it to work
properly.

The environment:
Athlon 2500+, 1G RAM
NForce2 board, onboard EHCI USB
Starbox is the only connected USB device

Starbox is working fine under Windows, so I do not think it is a
hardware problem.

Gentoo 2.6.13-rc3
dvb-kernel CVS Version from today
dvb-usb-vp702x.ko built as module, loaded by hotplug-20040923-r1

dmesg-output looks ok:
--code
usb 3-1: new device strings: Mfr=1, Product=2, SerialNumber=0
usb 3-1: Product: USB-VP702X
usb 3-1: Manufacturer: TWINHAN
usb 3-1: hotplug
usb 3-1: adding 3-1:1.0 (config #1, interface 0)
usb 3-1:1.0: hotplug
dvb-usb-vp702x 3-1:1.0: usb_probe_interface
dvb-usb-vp702x 3-1:1.0: usb_probe_interface - got id
dvb-usb: found a 'TwinhanDTV StarBox DVB-S USB2.0 (VP7021)' in warm state.
dvb-usb: will use the device's hardware PID filter (table count: 8).
DVB: registering new adapter (TwinhanDTV StarBox DVB-S USB2.0 (VP7021)).
dvb-usb: MAC address: 00:08:ca:15:3b:1f
vp702x: system string: USB702X
DVB: registering frontend 2 (Twinhan DST-like frontend (VP7021/VP7020)
DVB-S)...
dvb-usb: schedule remote query interval to 400 msecs.
dvb-usb: TwinhanDTV StarBox DVB-S USB2.0 (VP7021) successfully
initialized and connected.
--/code

I have had problems with usb in and out errors, but those seem to have
vanished with the latest kernel source I am using.
szapping kind of works:

--code
tvs dvb-kernel # szap -a 2 rtl
reading channels from file '/root/.szap/channels.conf'
zapping to 400 'RTL':
sat 0, frequency = 12207 MHz V, symbolrate 27500000, vpid = 0x0000, apid
= 0x0000
using '/dev/dvb/adapter2/frontend0' and '/dev/dvb/adapter2/demux0'
status 1f | signal 0000 | snr 0000 | ber 00000000 | unc 00000000 |
FE_HAS_LOCK
status 1f | signal 0000 | snr 0000 | ber 00000000 | unc 00000000 |
FE_HAS_LOCK
status 1f | signal 0000 | snr 0000 | ber 00000000 | unc 00000000 |
FE_HAS_LOCK
status 1f | signal 0000 | snr 0000 | ber 00000000 | unc 00000000 |
FE_HAS_LOCK
status 1f | signal 0000 | snr 0000 | ber 00000000 | unc 00000000 |
FE_HAS_LOCK
--/code

Now here come the questions:
signal, snr and all other data seem to be zeroed, although the frontend
appears to have locked. I checked in the vp702x-fe.c temporary frontend
driver and didn't see dummy code, it seems to be actually reading the
status from the box.
Is this supposed to happen? It seems to cause problems in the TV clients
I am trying - Mythtv can't fetch a PMT, xine can't find an input driver,
kaxtv crashes with a Seg fault.

Could anyone give me a pointer on where to look for the Frontend specs
so I could try and debug the frontend code? Or maybe someone has had
similar problems and can help?

I understand the driver is work in progress, and it is clearly marked as
Alpha, but I would really like to use it, even if I need to help debug
the stuff in the first place.

Thanks for your time,

--
Chris Scholz






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