DVB-T2 adaptor usable only once per disable-enable cycle

Ratchanan

So this is a weird one. I have an Astrometa DVB-T2 clone. After I added it to TVH, I can scan 1 mux, and then the rest of the muxes is not able to scan. But if I go to Configuration > DVB Inputs > TV adapters, then disable and re-enable the adapter, then I scan another mux. A similar behavior can be seen when I try to play a channel. It would be playable once, and then it becomes non-working. However, disabling and re-enabling the adapter makes it working again 1 time.

TVH is running in a Docker container. The system is a Rapsberry Pi 4 B running NixOS. The kernel is Raspberry Pi's vendor tree of Linux 6.6.72. The RPi is powered by Raspberry Pi's official power supply (pre RPi-5 one), so the power issue is not likely (while it's connected to an external HDD, it's powered by its own power supply).

Linked below is log from TVH right after restart. The first successful subscription is the one from 'epggrab', but any subscription attempt after that fails. At that point, a log line "linuxdvb: Sony CXD2837ER DVB-T/T2/C demodulator #0 : DVB-T #1 - poll TIMEOUT" appears. (Note: I'm unable to get debugging output to print by configuring on the webui. Any suggestion on this one is appreciated.)

https://termbin.com/p919

And this is kernel dmesg. I don't see anything unusual about this one - no failed firmware request or something like that.

https://termbin.com/jtt7

DeltaMikeCharlie

In the TVH log, there is a "Poll Timeout" error message.

Here are some postings from some other users that may be useful:

https://tvheadend.org/d/6802-help-with-drivers-dvb-c-0-poll-timeout

Try to disable "idle scan muxes".

https://tvheadend.org/d/8814-poll-timeout-on-realteksony-usb-dvb-t2-when-switching-muxes/5

Check your Linux Kernel version for compatibility, there seems to have been issues in the past.

https://discourse.osmc.tv/t/no-dvb-t-channels-in-tvheadend-after-latest-update/102586/4

Check your antenna lead.

https://www.tbsdtv.com/forum/viewtopic.php?f=87&t=25688

Try tweaking your 'status period'.

Ratchanan

DeltaMikeCharlie Thank you for your suggestion. Unfortunately it doesn't help in my case.

What helps, however, is making sure that "Power save" is enabled in the adapter settings, and also to make sure the adapter is disabled and re-enabled once more after "Power save" is set.

From reading the code, this settings seem to make sure that the frontend device is closed when there's nothing in TVH using it, which seems to simulate the effect of disable-enable cycle.

I suspect that this might be some sort of kernel driver issue where it doesn't handle holding device open and then re-using it or something. Although, for my use case the problem is now solved, so I'll leave that as a mystery for someone else. 😛