[linux-dvb] [PATCH] Multi protocol support (stage #1)

Manu Abraham abraham.manu at gmail.com
Mon Jun 12 23:24:31 CEST 2006


Johannes Stezenbach wrote:
> Anyway, it needs to be implemented first and proven to
> work (especially wrt backwards compat) before it can be merged
> into mainline. 

Regarding backward compatibility, the best thing to do is to maintain 
the IOCTL's FE_SET_FRONTEND/FE_GET_FRONTEND as it is alongwith the 
callbacks that which it uses right now ..

So in this case we don't change anything at all.

Now when we add in support/change driver status one by one (this helps 
in no need to rush, we fix them one by one in a relaxed state of mind) 
we just add in the new callbacks, fe_get_params/fe_set_params or 
search/track.

A lazy mans approach, leaving nothing broken and things to the state 
that which it was working originally.
Even apps can migrate to it slowly.

there are 2 kinds of drivers
(1) dumb devices
(2) devices that implement tuning algorithms

for (1) we use fe_set/get_params and for (2) we use search/track
Currently, only the stb0899 supports the callbacks search and track

AFAICS after having discussions with ADQ and RJKM a while back, most of 
the frontend drivers can be made to do (2) only very few need to do (1) 
But since this involves quite some changes at the driver level, it is 
indeed a time consuming thing altogether. I think i explained the case 
earlier that which the stv0299 can be made to do, this similarly others 
can also be made to do in similar ways.

This will improve the tuning time required etc by the demods.


Manu




More information about the linux-dvb mailing list