Re: [patch] video: build fix for drivers/media/video/mt9v022.c

[Ingo Molnar <mingo@elte.hu>]

* Guennadi Liakhovetski <g.liakhovetski@gmx.de> wrote:

> > with this config:
> > 
> >    http://redhat.com/~mingo/misc/config-Sat_May__3_16_08_39_CEST_2008.bad
> > 
> > the bug was that the driver uses GPIO functionality but only 
> > includes the GPIO interface definitions for the 
> > CONFIG_MT9M001_PCA9536_SWITCH case, which was not set in this 
> > config.
> 
> Ok, once again a good catch and a wrong fix, sorry :-) The bug is that 
> not CONFIG_MT9M001_PCA9536_SWITCH but CONFIG_MT9V022_PCA9536_SWITCH 
> shall be checked for, of course. Copy-paste:-( I'll prepare a correct 
> patch and submit it. As for the "cleanup" side - don't know. Would it 
> be better to unconditionally include it? It won't hurt of course, 
> looks better, but is unneeded when the GPIO is not used. And, although 
> grep reports most drivers including asm/gpio.h, including linux/gpio.h 
> seems indeed better.

No. If you look at the core kernel you wont see it sprinkled with things 
like:

 #ifdef CONFIG_LOCKDEP
 #include <linux/lockdep.h>
 #endif

why? Because we have put all such things into the include file 
themselves and do not want to sprinkle .c files with ugly #ifdefs. This 
is a basic cleanliness issue.

Furthermore, if anyone _else_ copy & pastes your driver, this bug wont 
hit him anymore.

so please keep that #include <linux/gpio.h>.

	Ingo