On Mon, 9 Feb 2009 20:01:05 -0800 (PST) Trent Piepho <xyzzy@xxxxxxxxxxxxx> wrote: > ... > > I took some time during this kernel cycle trying to fix mpeg dependencies. One > > issue that I had to deal with is that some possible configurations with CX88, > > CX88_BLACKBIRD and CX88_DVB causes breakages (weird configs like having one as > > M and others as Y). Those weird configurations don't have any practical usage, > > but causes lot of headaches at the Kconfig logic. > > Both of the methods I've show will work 100% correctly with any combination > of Y, M, and so on. > > > I suspect that the current way compiles fine in-kernel, but maybe the > > I don't think it will. It's going to set MPEG to 'y' when CX88_VIDEO is > 'm' because the default line will override the dependency. Trying to avoid > select by using "default X if ..." lines has the same problem as select: > dependencies are ignored. It's worse than select since it's more complex > and fails on various odd cases like one 'y' and one 'm'. > ... > > > > I almost used a similar logic like above (just replacing tristate by boolean on > > CX88_DVB and CX88_BLACKBIRD to avoid the weird and unpractical kconfigs). > > I agree that adding more questions to the poor end-user is evil. So, I decided > > for a hidden var for CX88_MPEG, than adding a meaningless option (on the user > > POV), on the latest CX88 Kbuild changeset. > > Is the latest CX88 kbuild changeset different than what's in Hg now? I > think my patch with select is the best way. There is no reason that MPEG > would depend on something that DVB and BLACKBIRD don't, so there is no > problem with select. There is also no problem with MPEG getting selected > from many places throughout the kernel which might not have the right > dependencies, since nothing besides DVB and BLACKBIRD are going to select > it. Take a look on the changesets I'm referring: changeset: 10190:eb1848dcb073 user: Mauro Carvalho Chehab <mchehab@xxxxxxxxxx> date: Tue Jan 06 17:06:07 2009 -0200 summary: cx88: Fix some Kbuild troubles changeset: 10191:7c430437c967 user: Mauro Carvalho Chehab <mchehab@xxxxxxxxxx> date: Wed Jan 07 00:53:22 2009 -0200 summary: cx88: Fix Kconfig MPEG dependencies There is a large descriptionon 10190 explaining what were the issues. I had even to touch inside the code to avoid breakages, since, otherwise, things like this would break compilation: CONFIG_VIDEO_CX88=y CONFIG_VIDEO_CX88_BLACKBIRD=y CONFIG_VIDEO_CX88_DVB=m CONFIG_DVB_CORE=m Btw, at the in-kernel compilation, if you do something like: config FOO depends on BAR default y if BAR is m, then FOO is also m; if BAR is n then FOO is n. I've checked it, and also, this is what Roman (Kbuild maintainer) recommended us as a way to avoid the usage of select: http://lkml.org/lkml/2008/5/25/220 I suspect that the issue is on the parsing rules on our build system. I would like to have the offended .config, in order to test against 2.6.29-rc and see if we have such troubles upstream. Cheers, 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
