Hi Robert, On Fri, Feb 24, 2012 at 11:40 AM, Robert P. J. Day <rpjday@xxxxxxxxxxxxxx> wrote: > > i'm fairly sure i know the answer to this, but i figured i'd run it > by others just to make sure i'm not missing anything subtle. > > in drivers/video/omap2/Makefile, we see: > > ... snip ... > obj-$(CONFIG_OMAP2_DSS) += dss/ > obj-$(CONFIG_FB_OMAP2) += omapfb/ > obj-y += displays/ > ... snip ... > > and when i see "obj-y", i like to assume that's a component that will > be compiled unconditionally. but if you look at the Kconfig file in > the displays/ directory, you see: > > menu "OMAP2/3 Display Device Drivers" > depends on OMAP2_DSS > ... entire file contents ... > endmenu > > but that suggests that that entire subdirectory depends on > OMAP2_DSS, so one could remove the dependency from that Kconfig file > and just move it up to the Makefile above: > > obj-$(CONFIG_OMAP2_DSS) += displays/ > > correct? i prefer that approach since the dependency is obvious from > the Makefile, without having to descend into the directory itself to > learn of it. > > thoughts? is there anything i'm not noticing about this? There is one subtle difference. 1 - Configure such that CONFIG_OMAP2_DSS is set and do a build 2 - Configure such that CONFIG_OMAP2_DSS is not set and do a clean When obj-y += displays is used, the clean will clean out the displays directory When obj-$(CONFIG_OMAP2_DSS) is used, then the clean won't clean out the displays directory, and I think you can wind up with the unclean built-in.o being compiled into your kernel, but I'm not 100% on that. As long as you did the clean before changing the config, you'd not see any difference. -- Dave Hylands Shuswap, BC, Canada http://www.davehylands.com _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
