Kernel 2.6.29 Mandriva 2009.1 and Mythbuntu 9.04. Same thing in either box. Both tuners register 2 frontends just fine. Assign cards in mythtv fine. but watch tv gets no lock, and no signal. Oh, firmware dvb-fe-xc5000-1.6.114.fw is installed. Femon output for both tuners the same.

[wes@wes2 ~]$ femon -a 2
using '/dev/dvb/adapter2/frontend0'
FE: Samsung S5H1411 QAM/8VSB Frontend (TERRESTRIAL)
status 01 | signal 0000 | snr 0000 | ber 00000000 | unc 00000000 |
status 01 | signal 0000 | snr 0000 | ber 00000000 | unc 00000000 |
status 01 | signal 0000 | snr 0000 | ber 00000000 | unc 00000000 |
status 01 | signal 0000 | snr 0000 | ber 00000000 | unc 00000000 |

Any clues anyone?

OK, if you have a newer revision of this card (silkscreen showed rev 1.1, lspci showed rev 04) it is not supported in the kernel yet and you will have to install the latest (dated Aug 1) v4l drivers from linuxtv.org. The firewire driver wouldn't make for me, so you may have to run xconfig, etc, to disable it. After that, it makes and installs fine. Just thought I'd follow up on this in case others have this card. Don't know when the new drivers will make it into the kernel.