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

Philip Prindeville philipp_subx at redfish-solutions.com
Wed Nov 16 05:26:30 CET 2005


Manu Abraham wrote:

> Johannes Stezenbach wrote:
>
>> - program PLL for frequency to scan
>> - program demod for scanning
>> - poll some demod register until it signals completion
>>  (or use irq if available)
>>  
>>
>
> This is possible with the adaptive algo in the sense that the relevant 
> function can return values for the relevant . For example, 
> center_carrier()  returns the status when that operation is complete 
> etc ..
>
>> - pass result to userspace (e.g. event, wake up poll(2), ioctl)
>>  
>>
>
> But these functions, i think will need to stay in kernel, to avoid too 
> many transactions, IOCTL's from userspace to the driver.


Sure...  Plus that would complicate scheduling, locking, etc. in a user
application, especially if it was multi-threaded...

-Philip



>> - repeat
>>
>> I know the driver software from the fe vendors often uses
>> floating point and makes it look complicated, but IMHO
>> it doesn't have to.
>>
>>  
>>
> - get frequency step for reprogramming PLL from driver
>
> Yeah, i have a small implementation without that complication, but not 
> yet finished though.
>
>
> Manu
>
>
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