Re: open and close semanthics

[Florian Tobias Schandinat <FlorianSchandinat@gmx.de>]

Hi,

this is not authoritative but I hope that's better than no answer:

Alessio Sangalli schrieb:
> Hi, can somebody give me an authoritative answer:
> what is the semanthics associated to the "open" and "release" (close) calls?
> 
> More specifically, "open" and "release" can/must/must not change any 
> setting (resolution etc)?
> 
> Should those functions keep a "counter" of how many programs opened it?

I'd say that's not well defined. skeletonfb lists them even as optional. 
I've read that some drivers use it for mode changes, some keep counters 
and others just return 0.
If you are writing a driver: use it as you need it or don't use it at all.
If you write something that needs this behavior: there is none you can 
expect along all drivers, sorry.

For more information:
http://www.linux-fbdev.org/HOWTO/4.html
<linux kernel tree>/drivers/video/skeletonfb.c


Regards,

Florian Tobias Schandinat

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