Em 24-08-2011 10:25, Laurent Pinchart escreveu: > Hi Vaibhav, > > On Wednesday 24 August 2011 14:19:01 Hiremath, Vaibhav wrote: >> On Wednesday, August 24, 2011 5:00 PM Laurent Pinchart wrote: >>> On Wednesday 24 August 2011 13:21:27 Ravi, Deepthy wrote: >>>> On Wed, Aug 24, 2011 at 4:47 PM, Laurent Pinchart wrote: >>>>> On Friday 19 August 2011 15:48:45 Deepthy Ravi wrote: >>>>>> From: Vaibhav Hiremath <hvaibhav@xxxxxx> >>>>>> >>>>>> Fix the build break caused when CONFIG_MEDIA_CONTROLLER >>>>>> option is disabled and if any sensor driver has to be used >>>>>> between MC and non MC framework compatible devices. >>>>>> >>>>>> For example,if tvp514x video decoder driver migrated to >>>>>> MC framework is being built without CONFIG_MEDIA_CONTROLLER >>>>>> option enabled, the following error messages will result. >>>>>> drivers/built-in.o: In function `tvp514x_remove': >>>>>> drivers/media/video/tvp514x.c:1285: undefined reference to >>>>>> `media_entity_cleanup' >>>>>> drivers/built-in.o: In function `tvp514x_probe': >>>>>> drivers/media/video/tvp514x.c:1237: undefined reference to >>>>>> `media_entity_init' >>>>> >>>>> If the tvp514x is migrated to the MC framework, its Kconfig option >>>>> should depend on MEDIA_CONTROLLER. >>>> >>>> The same TVP514x driver is being used for both MC and non MC compatible >>>> devices, for example OMAP3 and AM35x. So if it is made dependent on >>>> MEDIA CONTROLLER, we cannot enable the driver for MC independent >>>> devices. >>> >>> Then you should use conditional compilation in the tvp514x driver itself. >>> Or >> >> No. I am not in favor of conditional compilation in driver code. > > Actually, thinking some more about this, you should make the tvp514x driver > depend on CONFIG_MEDIA_CONTROLLER unconditionally. This doesn't mean that the > driver will become unusable by applications that are not MC-aware. > Hosts/bridges don't have to export subdev nodes, they can just call subdev > pad-level operations internally and let applications control the whole device > through a single V4L2 video node. > >>> better, port the AM35x driver to the MC API. >> >> Why should we use MC if I have very simple device (like AM35x) which only >> supports single path? I can very well use simple V4L2 sub-dev based >> approach (master - slave), isn't it? > > The AM35x driver should use the in-kernel MC and V4L2 subdev APIs, but it > doesn't have to expose them to userspace. I don't agree. If AM35x doesn't expose the MC API to userspace, CONFIG_MEDIA_CONTROLLER should not be required at all. Also, according with the Linux best practices, when #if tests for config symbols are required, developers should put it into the header files, and not inside the code, as it helps to improve code readability. From Documentation/SubmittingPatches: 2) #ifdefs are ugly Code cluttered with ifdefs is difficult to read and maintain. Don't do it. Instead, put your ifdefs in a header, and conditionally define 'static inline' functions, or macros, which are used in the code. Let the compiler optimize away the "no-op" case. So, this patch is perfectly fine on my eyes. Regards, Mauro -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
