Re: [BUG] Problem with LV5TDLX DVB-T USB and the 3.7.1 kernel

[Antti Palosaari <crope@iki.fi>]

On 01/05/2013 04:05 PM, Jacek Konieczny wrote:
> Hi,
>
> I have a 'NOT Only TV DVB-T USB Deluxe' tuner device:
>
> Model name: LV5TDLX DVB-T USB
> P/N: STLV5TDLXT702
> S/N: LV5TDLX120700116
> USB ID: 1f4d:c803
>
> This is based on the RTL2838UHIDIR chip with e4000 tuner (at least, that
> is detected by various drivers).
>
> I had some minor success with it with some old 3.x kernel and the
> drivers from:
>
> https://github.com/tmair/DVB-Realtek-RTL2832U-2.2.2-10tuner-mod_kernel-3.0.0
>
> This stopped working with kernel 3.5 and would not even build with newer
> kernels.
>
> Then I tried drivers from linuxtv.org, with little success. The RTL2838u
> driver has been recently included in the upstream kernel (3.7), so I
> have tried that (3.7.1). The hardware is detected, but I am not able to
> tune in.
>
> The signal is good - tested with my TV set. The USB tuner device is also
> OK, I have tried it with Windows and the software provided with the
> device and the same channels are available as on the TV.
>
> So the driver must be broken. Any ideas how can I debug or fix that?
>
> dmesg:
>> [ 3336.916384] usb 2-4: new high-speed USB device number 7 using ehci_hcd
>> [ 3337.051822] usb 2-4: New USB device found, idVendor=1f4d, idProduct=c803
>> [ 3337.051829] usb 2-4: New USB device strings: Mfr=1, Product=2, SerialNumber=3
>> [ 3337.051835] usb 2-4: Product: RTL2838UHIDIR
>> [ 3337.051839] usb 2-4: Manufacturer: Realtek
>> [ 3337.051843] usb 2-4: SerialNumber: 00000001
>> [ 3337.072145] usb 2-4: dvb_usb_v2: found a 'Trekstor DVB-T Stick Terres 2.0' in warm state
>> [ 3337.072194] usbcore: registered new interface driver dvb_usb_rtl28xxu
>> [ 3337.136867] usb 2-4: dvb_usb_v2: will pass the complete MPEG2 transport stream to the software demuxer
>> [ 3337.136886] DVB: registering new adapter (Trekstor DVB-T Stick Terres 2.0)
>> [ 3337.147449] usb 2-4: DVB: registering adapter 0 frontend 0 (Realtek RTL2832 (DVB-T))...
>> [ 3337.163939] i2c i2c-7: e4000: Elonics E4000 successfully identified
>> [ 3337.174823] Registered IR keymap rc-empty
>> [ 3337.174928] input: Trekstor DVB-T Stick Terres 2.0 as /devices/pci0000:00/0000:00:1d.7/usb2/2-4/rc/rc0/input15
>> [ 3337.174989] rc0: Trekstor DVB-T Stick Terres 2.0 as /devices/pci0000:00/0000:00:1d.7/usb2/2-4/rc/rc0
>> [ 3337.174994] usb 2-4: dvb_usb_v2: schedule remote query interval to 400 msecs
>> [ 3337.187693] usb 2-4: dvb_usb_v2: 'Trekstor DVB-T Stick Terres 2.0' successfully initialized and connected
>
> Scanning on one of the available channels:
>> # tzap -r "TVP2"
>> using '/dev/dvb/adapter0/frontend0' and '/dev/dvb/adapter0/demux0'
>> reading channels from file '/root/.tzap/channels.conf'
>> tuning to 746000000 Hz
>> video pid 0x00ca, audio pid 0x00cb
>> status 00 | signal bfe1 | snr 0000 | ber 0000ffff | unc bfe14648 |
>> status 00 | signal bfe1 | snr 0000 | ber 0000ffff | unc bfe14648 |
>> status 00 | signal bfe1 | snr 0000 | ber 0000ffff | unc bfe14648 |
>> status 00 | signal bfe1 | snr 0000 | ber 0000ffff | unc bfe14648 |
>> status 00 | signal bfe1 | snr 0000 | ber 0000ffff | unc bfe14648 |
>> status 00 | signal bfe1 | snr 0000 | ber 0000ffff | unc bfe14648 |
>> status 00 | signal bfe1 | snr 008c | ber 00004ca0 | unc bfe14648 |
>> status 00 | signal bfe1 | snr 0000 | ber 0000ffff | unc bfe14648 |
>> status 00 | signal bfe1 | snr 008d | ber 00004ca0 | unc bfe14648 |
>> status 00 | signal bfe1 | snr 0000 | ber 0000ffff | unc bfe14648 |
>> status 00 | signal bfe1 | snr 0072 | ber 00004ca0 | unc bfe14648 |
>> status 00 | signal bfe1 | snr 0000 | ber 0000ffff | unc bfe14648 |
>> status 00 | signal bfe1 | snr 008b | ber 00004ca0 | unc bfe14648 |
>> status 00 | signal bfe1 | snr 0000 | ber 0000ffff | unc bfe14648 |
>
> And on the other one:
>> # tzap -r "Polsat"
>> using '/dev/dvb/adapter0/frontend0' and '/dev/dvb/adapter0/demux0'
>> reading channels from file '/root/.tzap/channels.conf'
>> tuning to 698000000 Hz
>> video pid 0x0066, audio pid 0x0067
>> status 00 | signal bfb5 | snr 0000 | ber 0000ffff | unc bfb5f4d8 |
>> status 00 | signal bfb5 | snr 0000 | ber 0000ffff | unc bfb5f4d8 |
>> status 00 | signal bfb5 | snr 0000 | ber 0000ffff | unc bfb5f4d8 |
>> status 00 | signal bfb5 | snr 0000 | ber 0000ffff | unc bfb5f4d8 |
>> status 00 | signal bfb5 | snr 0000 | ber 0000ffff | unc bfb5f4d8 |
>> status 00 | signal bfb5 | snr 0000 | ber 0000ffff | unc bfb5f4d8 |
>> status 00 | signal bfb5 | snr 0000 | ber 0000ffff | unc bfb5f4d8 |
>> status 00 | signal bfb5 | snr 0000 | ber 0000ffff | unc bfb5f4d8 |
>> status 00 | signal bfb5 | snr 0000 | ber 0000ffff | unc bfb5f4d8 |
>> status 00 | signal bfb5 | snr 0000 | ber 0000ffff | unc bfb5f4d8 |
>> status 00 | signal bfb5 | snr 0000 | ber 0000ffff | unc bfb5f4d8 |
>> status 00 | signal bfb5 | snr 0000 | ber 0000ffff | unc bfb5f4d8 |
>> status 00 | signal bfb5 | snr 0000 | ber 0000ffff | unc bfb5f4d8 |
>
> Greets,
> 	Jacek
>

It is likely e4000 driver bug. It is not optimized nor tested very well 
- just few live multiplexes I have here. You are the first one reporting 
(performance?) issues like that, I am quite sure it works somehow well 
for the most.

Take USB sniffs, make scripts to generate e4000 register write code from 
the sniffs, copy & paste that code from the sniffs until it starts 
working. After it starts working it is quite easy to comment out / tweak 
with driver in order to find problem. With the experience and luck it is 
only few hours to fix, but without a experience you will likely need to 
learn a lot of stuff first.

Of course those sniffs needed to take from working case, which just 
makes successful tuning to 746000000 or 698000000.

Also you could use to attenuate or amplifier signal to see if it helps.

I don't have much time / money, no interest, no equipment (DVB-T 
modulator) to start optimizing it currently.

regards
Antti

-- 
http://palosaari.fi/