[linux-dvb] [patch] Add support for different tuning algorithms

Johannes Stezenbach js at linuxtv.org
Thu Nov 17 00:30:40 CET 2005


On Wed, Nov 16, 2005 Andrew de Quincey wrote:
> Was thinking - maybe we do need to move frequency scanning into the kernel for 
> optimum efficiency. It is going to have to be really frontend specific code 
> to get it as fast as possible, so I don't see we have much choice. We could 
> always implement a "dumb"/slow scanner as a fallback.
> 
> e.g. something like the following structure passed to an ioctl.
> 
> struct dvb_frontend_scan {
> 	__u32 start_freq;
> 	__u32 end_freq;
> 	__u32 step;
> };
> 
> Perhaps we would want to have other things - e.g. specify a bitmask of what 
> FECs, and other such parameters to test.
> 
> Felix's suggestion of just generating them as data to be read() from the 
> frontend device sounded ok to me. I suppose another option would be to 
> generate frontend events with the results, but I prefer read() myself.

There were some previous suggestions for a scanning API by
Roberto Ragusa and Holger Waechtler around Aug 1. 2004:
http://linuxtv.org/mailinglists/linux-dvb/2004/08-2004/threads.html#00003


Johannes



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