Michael Krufky wrote:
Yeasah Pell wrote:
After having my KWorld cx24123 card out on loan to a friend for a few
months, I've got it back in my system. The first thing I noticed is that
the LNB voltage is backwards -- setting it to 13V via ioctl produces 18V
on a meter connected to the coax, and vice-versa. It's a trivial fix of
course, but I think I remember seeing something on the list a while back
about cx24123 voltage being backwards (though I can't find it now, of
course)
Anybody remember?
Yes... This is the changeset that is causing the behavior that you have
described:
http://linuxtv.org/hg/v4l-dvb?cmd=changeset;node=71fd1c71d114
Hmmm... Either we misread the spec, or it was wrong. Perhaps the
information varies depending on how the demod is wired to the rest of
the board. The spec itself is somewhat unclear to me now. We know that
it is needed this way for the Geniatech Digistar / Digiwave 103g, and
the Hauppauge cards don't use this feature. If reverting it fixes things
for you, then we might have to conditionalize this somehow.
The spec just says that the LNBDC bit switches the LNB_DC output pin
between a logical high or low level (0V or 3.3V) -- it doesn't say
anything about what the LNB voltage control circuit might do with that,
and of course that depends on the rest of the circuit. There is another
control bit (LNBDCPol) which is designed to allow reversing the polarity
of the output without having to change the logic of the LNBDC bit value,
and it sounds like geniatech cards must have a different LNB regulator
circuit. As you say, the hauppauge uses an external SEC chip so it
doesn't apply to that card at all.
So we'll have to set LNBDCPol differently depending on the card type. No
big deal, just a register initialization change.
Please try reverting this changeset by doing:
hg export 71fd1c71d114 | patch -p1 -R
I'd assume that this will fix it for you -- please respond and confirm.
I had already fixed it by swapping it back -- I didn't know which change
it was that needed to be reverted so I didn't do it that way, but I can
confirm that it does work on the kworld card if you swap it back.
-y
_______________________________________________
linux-dvb@xxxxxxxxxxx
http://www.linuxtv.org/cgi-bin/mailman/listinfo/linux-dvb
