[linux-dvb] Re: backwards compatability -was- actual cvs broken?

Manu Abraham abraham.manu at gmail.com
Thu Nov 3 12:25:09 CET 2005


Edgar Toernig wrote:

>It should be possible to create a dummy bttv driver that only
>supplies GPIO and I2C access.  This dummy driver could even be
>part of the dvb-bt878 driver.  (I may be wrong but wasn't the
>first version of the dvb-bt878 driver like that?)  But you
>have to find someone who's willing spends some hours of work
>to do that :-)  I wouldn't - it's unsatisfying to invest a
>lot of work just to "remove" functionality.
>
>  
>

Yeah, i can understand your feelings. It is kind of very frustraing when 
working with a card than spans subsystems, especially when you have a 
layered module. I have been subjected to the extreme frustration a while 
back, that bttv in V4L used to get screwed up, resulting in breakages 
elsewhere. The clueless users will keep complaining that other modules 
are not functioning as expected. Well, this is really hard.

Well, this is the disadvantage of not having code duplication.

But the real aspect of it is, that if all modules were to have code 
duplication, imagine the sixe of the kernel, and maintainabilty issues.

The adavantage of not having code duplication is that bugs can be easily 
identified out, as the code review does not happen for a particular 
hardware, but happens in a generic manner.

The only way compatibility can be ensured is subsystems play nice to 
each other. A while back it was quite difficult to get dvb-kernel and 
CVS to play nice to each other. Anyhow that situation has improved a 
lot, and it is not as bad as it was earlier. Anyway, both aspects has 
their own merits and demerits.

Manu




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