[mythtv-users] DVB: changing adapter number

[Stephen Worthington]

On Sun, 11 Jan 2026 15:47:28 +0100, you wrote:

>Hi,
>
>     Whenever I reboot my back-end server, the DVB card can change there 
>adapter number, as documented in my previous email. The new MythTV setup 
>(MythTV 0.35) only accepts DVB adapter card with the /dev/dvb/adapterxx 
>syntax.  In order to use logical names, I have to modify directly the 
>database using :
>
>update capturecard set videodevice = '/dev/dvb/TBS6590-0/frontend1' 
>where cardid = 25 or cardid = 29;
>
>     Is there a better way of handling DVB card whose adapter number is 
>variable ?
>
>Regards,
>Alain Brossard
>

Most tuner drivers will accept an "adapter_nr=" option on the modprobe
driver options line.  Create a .conf file in /etc/modprobe.d and put
options lines in it.  Make sure the file is "chown root:root" and
"chmod u=rw,og=r".  You need to know the name of the driver that is
loaded for the card - you can usually find that in dmesg, kern.log or
syslog.  The output of a "modinfo <driver_name>" command lists all the
options the driver accepts in the "parm:" lines.

Once you have set an adapter_nr for a tuner, it will be able to be
used as:

/dev/dvb/adapter<adapter_nr>

When assigning adapter_nr values to more than one tuner that uses the
same driver, with PCI/PCIe cards the order the tuners are enumerated
by the kernel is the order they receive adapter_nr values from left to
right in the adapter_nr list.  The enumeration will only change if the
cards are moved to different slots.  I think that also applies to USB
tuners, but I am not sure.

This is what my /etc/modprobe.d/options-dvb.conf file looks like after
using many different tuners on my MythTV box (the old tuners are
commented out):

#Options for the /dev/dvb cards

##Set adapter numbers for Pinnacle PCTV nano stick (73e) USB tuner and
Nova-TD 500 DVB-T card (dual tuners) (they use the same driver).
#options dvb_usb_dib0700 adapter_nr=0,1,2
# Note: Only one PCTV nano stick is in use now, and it does not have
an aerial conncetion - it is just used for its IR receiver.
options dvb_usb_dib0700 adapter_nr=18

##Set adapter numbers for AverMedia AverTV DVB-T Volar USB tuner and
Nova-TD 500 DVB-T card (dual tuners) (they use the same driver).
#options dvb_usb_dib0700 adapter_nr=0,1,2

##Set adapter numbers for AverMedia AverTV DVB-T Volar USB tuner and
Pinnacle PCTV nano stick (73e) tuners (they use the same driver).
#options dvb_usb_dib0700 adapter_nr=0,1

##Set adapter numbers for KWorld DVB-T 399UR dual DVB-T USB tuner.
#options dvb_usb_af9015 adapter_nr=1,2

##Set adapter number for KWorld DVB-T TV Stick II 395UR USB tuner.
#options dvb_usb_af9015 adapter_nr=7

##Set adapter number for TeVii S470 DVB-S2 PCIe x1 card.
##options cx23885 adapter_nr=4 debug=9 v4l_debug=9
#options cx23885 adapter_nr=4

##Set number of loopback adapters for use with sasc-ng/ffdecsawrapper
card decryption software, and set the adapter numbers to use.
#options dvbloopback num_adapters=2 adapter_nr=5,6

# TBS6909 8 tuner DVB-S2 card and TBS6209 8 tuner DVB-T2 card (they
use the same tbsecp3 driver).
options mxl58x mode=1 inputs=1,1,1,1
#options mxl58x mode=0
#                               TBS6209           TBS6909
#                          ===== DVB-T2 ===== ===== DVB-S2 =======
options tbsecp3 adapter_nr=0,1,2,3,16,15,4,17,7,8,9,10,11,12,13,14
# Adapter   0-4 = DVB-T2 MythTV
# Adapter   5-6 = currently unused (no adapter mapped to these adapter
numbers)
# Adapter     7 = DVB-S2 EPG and channel scanning (via scripts)
# Adapter  8-14 = DVB-S2 minisatip or TVHeadend
# Adapter 15-16 = DVB-T2 minisatip or TVHeadend
# Adapter    17 = DVB-T2 EPG and channel scanning (via scripts)
# Note: The physical adapters 4 and 16 are swapped as 4 seems to be
faulty - it gets a lot of pixelation on the Maori multiplex.

#Set adapter number for TurboSight TBS5922 QBOX S2 DVB-S2 USB tuner.
#Note: This tuner is used via usbip on another PC.
options dvb-usb-tbsqbox22 adapter_nr=19