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

Manu Abraham abraham.manu at gmail.com
Thu Nov 3 21:05:44 CET 2005

Philip Prindeville wrote:

> Manu Abraham wrote:
>> 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
> What about putting the glue code into a pseudo-device module that both
> the V4L and DVB modules depend on?
Hello Philip,

Things are easier when said, than done.

What about, say send in some code implying what you mean to do. To 
kickstart, maybe you can try out with a single bridge driver. You can 
try for one card how it looks like, and if that looks good, then why 
shall we not ? Eventhough, I didn't follow what you meant. Any attempt 
to make things simpler would be beneficial to all.


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