Ubuntu 20.04 Kernel 5.4.0-84 PCI Card Digital Devices Max M4

[Detlef Bloch]

Ladies and gentlemen,

I hope this is the proper team to address the problem I encountered
lately with my ubuntu based home media server:

[1.] One line summary of the problem: 
Ubuntu 20.04 Kernel 5.4.0-84-generic x86_64 no longer initializes the internal PCI Card Digital Devices Max M4. 

[2.] Full description of the problem/report: 

After performing an 'apt dist-upgrade' to include Ubuntu 20.04 Kernel 5.4.0-84-generic the program 
Tvheadend 4.3-1978~g7757f0665 no longer recognizes any of the card's 4 adapters.

lsmod reports the presence of the modules ddbridge, dvbcore and mc, but none of the system devices
/dev/ddbridge/card0 and /dev/dvb/adapter0, /dev/dvb/adapter1, /dev/dvb/adapter2 and /dev/dvb/adapter3
have been created. 

Work around: In /etc/default/grub fix the os to use the last working kernel:

GRUB_DEFAULT="gnulinux-advanced-224ca183-60cf-40df-b7db-3c10f4700f5c>gnulinux-5.4.0-81-generic-advanced-224ca183-60cf-40df-b7db-3c10f4700f5c


With kind regards

Detlef Bloch