[mythtv-users] "Tuner 5 has an error"
mike.bibbings at gmail.com
Thu Apr 25 09:37:55 UTC 2019
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:
> 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
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
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:
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
see section on Delay starting the backend until tuners have initialized
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