Bug 15986

Created attachment 26400 [details]
Attempting to tune on 2.6.34

Initial tuning of the device on fails to tune with message "tuning failed!!!" in kernels newer than ~2.6.22.

Steps to reproduce:
1) Plug in DViCO FusionHDTV DVB-T Hybrid card
2) Add "options cx88xx card=46 tuner=72" to modprobe.d (may fail to detect card on warm boot)
3) Attempt initial scan with `scan /usr/share/dvb/dvb-t/au-Melbourne`

Scan will run, fail to detect any channels ("tuning failed!!!") and then report "ERROR: initial tuning failed".

Scan should lock onto channels and then dump channel information.

I've been trying to track down a driver regression in my DViCO FusionHDTV DVB-T Hybrid card that makes it impossible to tune to DVB stations. In recent kernels (anything in past two years) the card is detected and /dev/dvb tree is created but attempting to scan for channels only results in a 'tuning failed!!!'.

Note: On some occasions the card will not be auto-detected correctly (usually warm boot), so I have added "options cx88xx card=46 tuner=72" to /etc/modprobe.d/dvb.conf.

After some investigation I found a comment on https://help.ubuntu.com/community/MythTV/Install/Gutsy/Tuners that indicated that the card stopped working around the release of Gutsy 7.10. Since I had an old LiveCD on hand, I tried out Feisty and found that the card tuned fine, but in newer releases the tuning fails.

Grabbing a few different kernel releases I can see that tuning works quite happily on the 2.6.17 kernel (very old) but appears to have broken somewhere around 2.6.22. Bisecting the v4l-dvb tree has the card turning at r4675, unable to compile r4676 and r4677, then no /dev/dvb tree being created until r5333 where tuning no longer works.