[mythtv-users] "Tuner 5 has an error"

Thu Apr 25 17:19:10 UTC 2019

Stephen Worthington wrote at about 22:50:51 +1200 on Thursday, April 25, 2019:
 > On Thu, 25 Apr 2019 10:37:55 +0100, you wrote:
 > 
 > >On 25/04/2019 05:06, mythtv at kosowsky.org wrote:
 > >> I am using mythtv 29.1 under Ubuntu 18.04 running under kernel 5.0.9.
 > >>
 > >> I initially installed a Hauppauge WinTV-quadHD PC Express card that
 > >> provides 4 dvb inputs:
 > >> 	 /dev/dvb/adapter0/frontend0
 > >>   	 /dev/dvb/adapter1/frontend0
 > >>   	 /dev/dvb/adapter2/frontend0
 > >>   	 /dev/dvb/adapter3/frontend0
 > >>
 > >> The Frontend ID for all is: LGDT3306A VSB/QAM Frontend.
 > >>
 > >> I then added a Hauppauge WinTV-HVR-955Q (aka Hauppauge Digital TV
 > >> Tuner for Xbox One) USB tuner.
 > >>
 > >> That tuner is recognized by Linux as /dev/dvb/adapter4/frontend4.
 > >> It works fine with VLC.
 > >>
 > >> Mythtv recognis the card appropriately as /dev/dvb/adapter4/frontend4
 > >> with Frontend ID also LGDT3306A VSB/QAM Frontend.
 > >>
 > >> Everything seems fine, but I can't switch to the card input on LiveTV.
 > >> System info says "Tuner 5 has an error" with details:
 > >>         Tuner 4 [DVB: /dev/dvb/adapter4/frontend0] has an error
 > >> (Note numbering is off because I name them Tuner 0 through 4 whereas
 > >> System info seems to count them 1 to 5,
 > >>
 > >> The mythtv-setup configuration for the tuner is the exact same as the
 > >> other 4.
 > >>
 > >> When I cycle through the tuners on Live TV, I go from Tuner 0 to 1 to
 > >> 2 to 3 and back to 0.
 > >> (Note that when I type M->Source, I get only the first 3 tuners...)
 > >>
 > >> The syslog shows for each tuner switch (but no errors for the 'skipped' Tuner 4):
 > >> Apr 24 23:49:03 consult kernel: [83954.235912] dvb_frontend: dvb_frontend_get_frequency_limits: frequency interval: tuner: 42000000...870000000, frontend: 54000000...858000000
 > >> Apr 24 23:49:03 consult kernel: [83959.284003] dvb_frontend: dvb_frontend_get_frequency_limits: frequency interval: tuner: 42000000...870000000, frontend: 54000000...858000000
 > >>
 > >> Any hints on how to track down the 'error' for the last tuner.
 > >> _______________________________________________
 > >
 > >You can safely ignore the "dvb_frontend: 
 > >dvb_frontend_get_frequency_limits: ..." messages (they are due to an 
 > >omission in a V4L update, where they should only be output under debug 
 > >conditions, but the debug check line is missing).
 > >
 > >
 > > From a clean boot the output "dmesg | grep frontend" from a terminal 
 > >session will show the order of detection and allocation to 
 > >adapter<x>/frontend<y>
 > >
 > >
 > >Assuming that all required firmware files are in /lib/firmware/, my 
 > >initial guess (without seeing mythbackend.log) is that USB Tuner is not 
 > >completely initialised at mythtv-backend startup, so mythtv gives the 
 > >error message.
 > >
 > >A quick check to see if this is the problem is to stop and start 
 > >mythtv-backend as follows in a terminal session:
 > >
 > >sudo systemctl stop mythtv-backend
 > >
 > >sudo systemctl start mythtv-backend
 > >
 > >now using mythfrontend try LiveTV, If the error is no longer present it 
 > >means a race condition at startup
 > >
 > >A quick and dirty fix, as an interim only, is to delay mythtv-backend 
 > >startup by a fixed time:
 > >
 > >In a terminal on the machine running mythtv backend:
 > >
 > >sudo systemctl edit mythtv-backend.service and add the following two lines:
 > >
 > >[Service]
 > >ExecStartPre=/bin/sleep 20
 > >
 > >Then exit from the edit screen (it uses nano by default, so Ctrl+x, then
 > >y, then Return key) then  reboot the machine
 > >
 > >The real fix is more complicated, if the startup delay resolves your 
 > >issue there is more information at 
 > >https://www.mythtv.org/wiki/Systemd_mythbackend_Configuration
 > >
 > >see section on Delay starting the backend until tuners have initialized
 > >
 > >
 > >Mike
 > 
 > If you are right about the tuner taking too long to start up, then it
 > is much better to go directly to the correct systemd fix rather than
 > trying the dirty one that might not work.  Here are specific
 > instructions for the correct fix:
 > 
 > First, create this file in /etc/udev/rules.d:
 > 
 > root at mypvr:/etc/udev/rules.d# cat 99-tuner.rules
 > #
 > # Create systemd device units for capture devices
 > #
 > SUBSYSTEM=="video4linux", TAG+="systemd"
 > SUBSYSTEM=="dvb", TAG+="systemd"
 > SUBSYSTEM=="firewire", TAG+="systemd"
 > 
 > The 99-tuner.rules file needs to have the right ownership and
 > permissions:
 > 
 > sudo chown root:root /etc/udev/rules.d/99-tuner.rules
 > sudo chmod u=rw,g=r,o=r /etc/udev/rules.d/99-tuner.rules
 > 
 > Then create a systemd override file for mythtv-backend:
 > 
 > sudo systemctl edit mythtv-backend.service
 > 
 > In the override file, put this:
 > 
 > [Unit]
 > 
 > Wants=dev-dvb-adapter0-frontend0.device
 > After=dev-dvb-adapter0-frontend0.device
 > Wants=dev-dvb-adapter1-frontend0.device
 > After=dev-dvb-adapter1-frontend0.device
 > Wants=dev-dvb-adapter2-frontend0.device
 > After=dev-dvb-adapter2-frontend0.device
 > Wants=dev-dvb-adapter3-frontend0.device
 > After=dev-dvb-adapter3-frontend0.device
 > Wants=dev-dvb-adapter4-frontend0.device
 > After=dev-dvb-adapter4-frontend0.device
 > 
 > That will create a file
 > /etc/systemd/system/mythtv-backend.service.d/override.conf.  If you
 > already have an override file in that directory with a different name,
 > edit that and add the above to it.
 > 
 > Then reboot.
 > 
 > Now the mythtv-backend service will not be started until all those
 > devices exist, or a long timeout (90 seconds, I think) happens.  So if
 > the USB tuner is unplugged or faulty, mythbackend will take a long
 > time before it is started.
 > 
 > You can see the status of the mythtv-backend service with this
 > command:
 > 
 > systemctl status mythtv-backend
 > _______________________________________________

Thanks Steven.

If the problem were due to startup, wouldn't restarting mythtv-backend
manually well after boot(which I have tried multiple times) have solved this?

The devices presumably all exist and work fine since I have no problem
using the card under VLC. The dvb device even gets recognized properly
by mythbackend-setup.

Just when I try to actually use the device, it shows an error on Tuner 5.