On Thu, May 6, 2010 at 18:47, <Valdis.Kletnieks@xxxxxx> wrote: > On Thu, 06 May 2010 09:17:24 EDT, James Bottomley said: >> On Thu, 2010-05-06 at 08:47 +0200, Geert Uytterhoeven wrote: >> > On Wed, May 5, 2010 at 23:49, James Bottomley >> > <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx> wrote: >> > > [Sam: I know you don't maintain kbuild anymore, but since you have the >> > > most experience, if you could find time to comment, I'd be grateful] >> > > >> > > The select problem is that the kbuild select directive will turn a >> > > symbol on without reference to its dependencies. This, in turn, means >> > > that either selected symbols must select their dependencies, or that >> > > people using select have to be aware of the selected symbol's dependency >> > > and build those dependencies into their symbol (leading to duplication >> > > and the possibility of getting the dependencies out of sync). We use >> > > select for the scsi transport classes, so we run into this problem in >> > > SCSI quite a lot. >> > > >> > > I think the correct fix is to make a symbol that selects another symbol >> > > automatically inherit all of the selected symbol's dependencies. >> > >> > What if there's a good reason the selected symbol has this dependency? >> > E.g. it depends on a critical feature not available? Like CONFIG_HAS_IOMEM? >> >> I don't quite understand the question. If a selected symbol has a >> critical dependency which is config'd to N then the build usually >> breaks ... that's what I'm calling the select problem. I thought >> CONFIG_HAS_IOMEM was usually selected by the architecture, though. In >> the new proposal, we wouldn't be able to generate the invalid >> configuration in the first place. > > I think Geert is asking "If the arch says CONFIG_HAS_IOMEM=n, but some driver > does a 'select CONFIG_FOO' which then (under your proposal) forces the > value CONFIG_BAR=y, which eventually ends up with CONFIG_HAS_IOMEM=y, what > should the behavior be?" Yep, that was my (bogus) question... > (I suspect the right answer here is "one of the symbols is buggy and its > 'select' should be a 'depends' instead", but somebody else better double-check > that conclusion - I'm hardly a Kconfig expert). No, the CONFIG_FOO will inherit the dependency on CONFIG_HAS_IOMEM. Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html