hermann pitton wrote:
Hi,
Am Dienstag, den 19.09.2006, 16:51 -0400 schrieb Steven Toth:
In the windows driver we leave the LNA off at all times, but have a registry
override to allow users to enable it. It's a single LNA for both tuners -
hence, it has its problems.
Switching the LNA dynamically in a TV app isn't something the API allows. How
about a module load param?
As updating an LNA (or something else) is very board specific, I put
callback "update_lna" in dib3000mc_config. I will call this after starting
the AGCs to see if the LNA has to be turned on or not (taking the agc
response into account). For that I would like to know, what is the gain of
the LNA when turned on? (So that I can adjust the thresholds when to turn
on or off). Maybe we need to make an average of both channels, not that we
kill one channel by only taking the other one into account.
Or is a module_parameter enough? (I don't like this, because the majority
of users does not even now what is a module, which is good).
Image a user that lives somewhere between two broadcast towers. They
receive some muxes at fairly weak levels and some very strong
(environment depending). We never found a good automatic solution to
deal with that within the (windows) driver.
If the driver can be made to work reliably for all users in Linux under
all circumstances then that's ideal. :)
Otherwise, the user may need some way to dictate LNA behavior.
looks like it is all because we are poor hackers ;)
On the contrary.
With reliable data sheets signal strength and/or ber rates should
indicate when to switch.
Last I looked Dibcom and Microtune hadn't released public datasheets for
their parts.
If tuner 1 is active on a strong mux, enabling a single LNA for tuner 2
(so a weak signal can be selected) may end up adding 10db to tuner 1
leading to problems.
I'm simply saying be careful with implementing policy for a single LNA
that effects multiple tuners, especially if the user has no choice about
how the LNA is controlled.
Looks similar like the situation on analog radio. Guess _nobody_ knows
how to read auxiliary bits and recently a little more for all tuners
around to get at least stereo/signal strength ...
A lot of datasheets are available for tuners. I don't know why this
would be a problem if someone decided to implement it.
Regards,
Steve
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