[linux-dvb] [PATCH] wscan: improved frontend autodetection

Darron Broad darron at kewl.org
Thu Nov 6 18:39:13 CET 2008

In message <49131C19.1080404 at gmx.de>, wk wrote:


>Hans Werner wrote:
>> Currently wscan will not autodetect frontends which which have frontend != 0,
>> i.e. it only detects /dev/dvb/adapterN/frontend0 where N=0-3.
>> Since multiple frontends per adapter are supported in 2.6.28, this means the correct
>> frontend may not be found. For example with the HVR4000, DVB-T is always at frontend1.
>> The attached patch fixes this, searching for frontend 0-3 for each adapter 0-3.
>> Signed-off-by: Hans Werner <hwerner4 at gmx.de>
>Good idea. :)
>But while testing your patch it seems that it doesn't work as expected. 
>Here some example:
>w_scan version 20081106
>Info: using DVB adapter auto detection.
>   Found DVB-C frontend. Using adapter /dev/dvb/adapter0/frontend0
>   Found DVB-C frontend. Using adapter /dev/dvb/adapter1/frontend0
>   Found DVB-C frontend. Using adapter /dev/dvb/adapter2/frontend0
>Info: unable to open frontend /dev/dvb/adapter3/frontend1'
>Info: unable to open frontend /dev/dvb/adapter3/frontend2'
>Info: unable to open frontend /dev/dvb/adapter3/frontend3'
>-_-_-_-_ Getting frontend capabilities-_-_-_-_
>I'm using three dvb-c frontends.
>The detection doesnt stop anymore with your patch if a matching frontend 
>was found, because it doesnt leave the outer loop.
>Normally this search has to stop at /dev/dvb/adapter0/frontend0.
>That means we have to change your patch a little. I also increased the 
>number of adapters to 8, since i use more than 4.
>Can you please test the attached patch and give some feedback? If it 
>works fine for you, i would apply to w_scan.
>PS: What is actually the maximum number of adapters and frontends per 
>adapter? Can anybody give some hint?

In relation to what Hans is addressing (Mutually exclusive frontends
on a single adapter AKA multi-frontend AKA MFE) then in theory the
core code is is not limited yet in practice there is a fixed provision
for two as that's the most that has been seen as yet.



 // /
{:)==={ Darron Broad <darron at kewl.org>
 \\ \ 

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