[linux-dvb] Re: [RFC][ANNOUNCE] blindscan: auto search everything

[Johannes Stezenbach <js@convergence.de>]

Roberto Ragusa wrote:
> 
> OK, so I propose this:
> 
> - you use FE_SET_FRONTEND as usual
> - then, you call FE_SET_AUTO_SEARCH passing something as
> 
> struct dvb_autosearch {
> 	fe_autosearch_t	parameter;
> 	__u32		lower limit;
> 	__u32		higher limit;
> }
> 
> typedef enum fe_autosearch_t {
> 	FE_AUTO_SYMBOL_RATE
> }
> 
> - then you use FE_GET_FRONTEND to read the sr

If I understand it correctly, all parameters passed
to FE_SET_FRONTEND would be set to AUTO, except for the
frequency? If so, then it would make more sense to me
to add the frequency to struct dvb_autosearch, and not
use FE_SET_FRONTEND for scanning.
This also needs to avoid the zigzag scan which FE_SET_FRONTEND
normally does.

(BTW, typedefs are deprecated for kernel code (only allowed
for explicitly opaque data types)).

> Thinking about it, we're converging to the original idea
> from Holger.
> But we shouldn't merge all the paramers together as he has done
> in his example, so we save hw independence.
> 
> He proposed many ioctl (START_SCAN, CONTINUE_SCAN, STOP_SCAN),
> and they may be useful in the future even if they are not needed
> at the moment.

These are only useful if the hardware can indeed scan a frequency
range automatically. If not, they are useless as userspace can
only check (a small band around) one frequency, and retrieve the
result (no signal, or a full parameter set). So please check
the data sheets again (for mt352 and mt312) to see if this is
true.


Johannes