Tuner not always detected/initialised correctly

m j

Sometimes (I've not yet noticed a discernible pattern) when tvheadend starts it is unable to use my tuner. The symptoms are as follows:
* Recording scheduled fail with "Time Missed"
* Attempting to tune to a channel in XBMC will give the error "No Hardware Present".
* The Status page of the Web UI shows 0% signal

Invariably, the problem can be solved by running @sudo service tvheadend restart@.

My set-up is as follows:
* Ubuntu 12.04 LTS
* Tvheadend 3.4.27~gfbda802~precise
* [[PCTV Nanostick T2]] (shows on Tvheadend Status page as Sony CXD2820R).

Does anyone have any ideas of how I can stop this happening, or failing that, how to detect if it's happened after boot and restart tvheadend from a script?

Cheers
Mark

ProfYaffle

Repeating what I said in another recent post... does this happen on a restart of the machine, by any chance? Linux tends to move USB devices around, which is fine if it's a keyboard but not so much use if you're expecting to find a tuner in a given place. You can tell because the adapter location will be blank, but a new adapter (with no services/channels) will appear on a different location (e.g. /dev/dvb1).

Post a screenshot of your adapter config page if you like, let's see if there's anything obvious. Check the drop-down to see if you have multiple tuners while you're there, and see what the config looks like for the others if you do.

m j

It happens "sometimes" on boot, rather than on restart specifically. I thought it might be something like that. Currently (it happened on this boot, but I've since restarted tvheadend), the device path is /dev/dvb/adapter0, which is what I'd expect. There's only one tuner in the drop-down on the config page. I've attached a screenshot in case there's anything useful there, I can do it again next time it happens before I restart tvheadend if that helps.

ProfYaffle

Please - grab that screen and check the dropdown before you restart.

Have a shufti at this thread as well, it might give you something to play with:

https://tvheadend.org/d/866-forcing-linux-to-assign-the-same-tv-card-to-the-same-dev-dvb-adaptorn-device

Looking back, I'm still left confused by what driver this stick uses, but if it's your only one then you should find it easily enough with lsmod - you can try the adapter_nr trick then. It's probably quicker to reboot your machine half-a-dozen times than it is to crack the udev route, sadly...!

m j

Ok, here's a screenshot when it's not working, before I restart tvheadend.

However, the tuner is still at /dev/dvb/adapter0, as expected:

mark@homestar:~$ ls -lR /dev/dvb/ /dev/dvb/: total 0 drwxr-xr-x 2 root root 120 May 7 17:47 adapter0 /dev/dvb/adapter0: total 0 crw-rw----+ 1 root video 212, 1 May 7 17:47 demux0 crw-rw----+ 1 root video 212, 2 May 7 17:47 dvr0 crw-rw----+ 1 root video 212, 0 May 7 17:47 frontend0 crw-rw----+ 1 root video 212, 3 May 7 17:47 net0

It's as though the tuner's being set up correctly by the OS, but not until after tvheadend has started. Does that make sense?

m j

Oh, and the dropdown on the config page only shows the one tuner.

ProfYaffle

I guess that's possible... it wouldn't explain why the tuner goes walkies during use, though, if that's what's happening. If that isn't what's happening, though, that's perfectly plausible.

I guess the test for your hypothesis would be simply to always restart tvheadend after a reboot, or add a delay - either a sleep in the start script, or perhaps re-order the upstart jobs so the tvheadend one runs later?

Can w_scan lock onto the tuner when it's in this state? That'd also help isolate things.

<pause>

Found this on a quick search if it's useful:

https://tvheadend.org/d/1278-startup-delay-waiting-for-dvb-tuners

m j

I've not noticed the tuner disappearing while watching/recording.

I've tried adding a delay using the TVH_DELAY setting in /etc/default/tvheadend, and it seems to be working. Thanks for your help.

ProfYaffle

Ah, yes - I thought I'd seen that, but couldn't find it in my file so assumed I'd imagined it. D'oh.