[mythtv-users] Satix S2 Dual regular dropouts / poor signal quality?

Sun Oct 10 08:23:14 UTC 2010

On 9 Oct 2010, at 22:14, Robert Longbottom wrote:

> Hi list,
> 
> I've just bought a Satix-S2 Dual to replace my existing HVR3000 and Technotrend S-1500.  I've set it up using the ngene driver from kernel 2.6.35.4 and the firmware linked to from the linuxtv wiki (http://linuxtv.org/wiki/index.php/Mystique_SaTiX_S2_Dual).  My plan was to retire the 2 PCI cards for a single dual PCIe card to free up some space in my case (for other cards ;-) ).
> 
> However after just a days testing of the Satix card I've had numerous failed recordings and dropouts mid recording (where recording just stops).  Also livetv regularly freezes and kicks me back to the main menu.

> 
> I've turned on the "record" log option for the backend and it the log when a recording stops half way through it reports:
> 2010-10-09 12:02:00.631 DevRdB(/dev/dvb/adapter103/frontend0) Error: Poll giving up
> 2010-10-09 12:02:00.640 DevRdB(/dev/dvb/adapter103/frontend0): fill_ringbuffer: error state
> 2010-10-09 12:02:00.648 DVBSH(/dev/dvb/adapter103/frontend0) Error: Device error detected
> 2010-10-09 12:02:00.648 DVBSH(/dev/dvb/adapter103/frontend0): RunTS(): shutdown
> 2010-10-09 12:02:00.648 PIDInfo(/dev/dvb/adapter103/frontend0): Closing filter for pid 0x0
> <snip>
> 2010-10-09 12:02:00.660 DVBSH(/dev/dvb/adapter103/frontend0): RunTS(): end
> 2010-10-09 12:02:00.701 DVBRec(1:/dev/dvb/adapter103/frontend0) Error: Stream handler died unexpectedly.
> Googling around, this looks like it's a signal problem, so I kicked off 'femon' against the dvb card.  It's reports values for Signal strength around 80%, SNR around 70%, UNC=0, BER is usually zero for one of the inputs and seems to be always 1 for the other input(?)  In comparison the HVR and the Technotrend report SNR values of >95%.  I'm using exactly the same two feeds from my dish into Satix as I have been for the past two years into the HVR and the Technotrend and in the past two years I don't think I've had a single failed recording due to a signal problem.
> 
> I'm also getting the following errors repeating quite a lot for the BBC channels in my logs, but that also happens with the old cards and it doesn't seem to matter there, so I'm guessing it isn't directly related to the problem:
> 2010-10-09 21:10:38.219 DVBRec(8:/dev/dvb/adapter101/frontend0): PID 0x138c discontinuity detected
> 2010-10-09 21:10:38.250 DVBRec(8:/dev/dvb/adapter101/frontend0): PID 0x13f0 discontinuity detected
> 2010-10-09 21:10:38.709 DVBRec(8:/dev/dvb/adapter101/frontend0): PID 0x138c discontinuity detected
> 2010-10-09 21:10:38.753 DVBRec(8:/dev/dvb/adapter101/frontend0): PID 0x13f0 discontinuity detected
> 2010-10-09 21:10:39.238 DVBRec(8:/dev/dvb/adapter101/frontend0): PID 0x138c discontinuity detected
> 
> 
> So the questions are...
> 
> Is anyone else using the Satix S2 Dual successfully?  If so, what values do you get for SNR? (I don't believe there is anything wrong with my dish / cabling because it's been working fine with the other two cards for a long time now)  Is the Satix just not as good at picking up the signal?

Femon doesn't seem very happy with the adaptor but this is what I see during a DVBS2 recording on first tuner.

Problem retrieving frontend information: Operation not supported
status SCVYL | signal  60% | snr  75% | ber 1 | unc 4328729 | FE_HAS_LOCK
Problem retrieving frontend information: Operation not supported
status SCVYL | signal  60% | snr  75% | ber 1 | unc 4328729 | FE_HAS_LOCK

Second tuner isn't connected...

We have an oversized dish and a well specified system (by me) in my building, we never see weather related fades so I can't really comment on the signal sensitivity.

> 
> According to a thread from back in April [1] there has been some success, but there was a lot of work pending on patches to the drivers.  Does anyone know if these patches have made it into the kernel yet?  Or should I try switching to the linux-dvb drivers rather than using the in-kernel drivers?

I'm using the v4l-dvb backports as 2.6.32-24 doesn't have working drivers for this card. I found that the prior to Devin's fixes I had both tuners working but with quite a few failed recordings, these would always fail to record anything from the start, haven't seen any mid recording failures. After Devin's fixes I had a lot fewer problems on the first tuner but the second is very unreliable. 

Around the time I bought the Satix S2 I was having serious sata problems in Ubuntu 9.04, upgrading to a newer kernel 2.6.35 and ultimately to 10.04 fixed these problems. I later replaced some disks that were having firmware problems with one of my sata controllers, I have since replaced the motherboard and have no problems with an ICH10 controller. This problem was showing as very regular glitches in all my HD recordings with corresponding kernel messages about disk restarts, I was also seeing disks dropping off the bus needing a power cycle to be restored. I'm detailing this because it wasn't until the sata problems were under control that I could see the remaining problems with the Satix card. For some reason (PCI v PCIe or in driver buffering differences perhaps) my HD S2 card was affected much more than the Satix.

So my current configuration which hasn't had a failed recording (fingers crossed) in many months and one glitch in ~ 20 recordings is:
v4l-dvb backports compiled on Ubuntu 10.04 2.6.32-24-generic 32bit kernel.
GRUB_CMDLINE_LINUX="vmalloc=256m"
Maximum timeout (2sec from memory) in the myth capture configuration.
Replaced all my Samsung F1 1TB drives for recordings.
Don't use the second tuner in the Satix S2
I have 4 multirec tuners per adapter.

I keep meaning to try the second tuner again but I have two DVBS cards as well and only four feeds from our communal satellite system.

I also follow the linux-media list looking for any updates, really I should moan at DVBShop to get something done about the driver, they sell it as a Linux product. I'm sure Kernellabs would be happy to be sponsored to fix the remaining problems.

Andre

> 
> Is there anything else I can do to work out why the signal seems to be so much worse on this card than on my other (old) cards?
> 
> I noticed on the digital devices site [2] there is what looks like a newer version of the firmware (ngene_17.fw).  I tried to use it, but it didn't work.  Presumably it's somehow tied to the driver version in the kernel?
> 
> How do I/can I fix the "discountinuity" errors?
> 
> Thanks!
> Robert.
> 
> [1] http://www.mythtv.org/pipermail/mythtv-users/2010-April/286115.html
> [2] http://www.digitaldevices.de/pageID_9262549.html
> 
> System Info:
> mythtv-0.23.1_p25496 on Gentoo Linux, kernel version 2.6.35.4
> 
> 
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