Messages in this thread | | | Date | Sun, 21 Oct 2007 21:42:29 -0700 | From | Randy Dunlap <> | Subject | Re: tristate and bool not enogh for Kconfig anymore |
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On Sun, 21 Oct 2007 20:14:16 -0700 Randy Dunlap wrote:
> On Sun, 21 Oct 2007 17:47:48 -0700 Randy Dunlap wrote: > > > On Sun, 21 Oct 2007 23:03:13 +0200 Sam Ravnborg wrote: > > > > > On Sun, Oct 21, 2007 at 09:45:17AM -0700, Randy Dunlap wrote: > > > > > Is there any other way to specify that a functionality can only be built > > > > > as a module, not built into the kernel? > > > > > > > > config FOO > > > > depends on BAR && m > > > > > > > > restricts FOO to module-only. > > > > > > > > > In my firsta attempts to post about these tests my post ended up not on > > > > > the mailing list but as a reply to Sam Ravnborg only, apologies for > > > > > that... > > > > > > This is obviously the right solution. > > > Randy - we should document this somewhere together with more kconfig tips'n'tricks. > > > > Agreed. > > So that's one tip or trick... or common idiom. > > > > A new document or do we extend kconfig-language? > > > > I don't see a need for a separate document. I would just extend > > kconfig-language. > > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > Another common idiom that we see (and sometimes have problems > with) is this: > > When B (module or subsystem) uses interfaces from A (module or > subsystem), A can be linked statically into the kernel image or > can be built as loadable module(s). This limits how B can be > built. If A is linked statically into the kernel image, B can be > built statically or as loadable module(s). However, if A is built > as loadable module(s), then B must be restricted to loadable > module(s) also. This can be expressed in kconfig language as: > > config B > depends on A = y || A = B > > > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > There's also a third issue: symbols that are specific to a > particular $arch, but they are in Kconfig files that are common > to all arches, so kconfig complains about symbol A refers to > unknown symbol B. (and I'm just writing this from memory, not > from testing it, so it could be off a bit.) One example of this > was PS3_PS3AV, as copied from an lkml email of 2007-feb-14: > > drivers/video/Kconfig:1604:warning: 'select' used by config symbol > 'FB_PS3' refer to undefined symbol 'PS3_PS3AV' > > Someone fixed this one by introducing an intermediate config symbol. > I didn't follow the details of that fix, but we see this problem > enough to warrant explaining how to handle it. E.g., recently > (from 2007-oct-14) on lkml: > > $ make oldconfig >/dev/null > drivers/macintosh/Kconfig:121:warning: 'select' used by config > symbol 'PMAC_APM_EMU' refers to undefined symbol 'APM_EMULATION' > > > > Adrian, do you know of other items that should be listed here?
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Continuing with real-life kconfig fun, here's a fourth item that people need to be aware of.
The construct:
if ARCH_OMAP source "drivers/video/omap/Kconfig" endif
does not prevent kconfig from reading drivers/video/omap/Kconfig. Instead, it make all config symbols in that file be dependent upon the ARCH_OMAP symbol. Adding a config symbol dependency like this is a common problem that causes config menus not to be displayed as they should be (not indented or not subordinate as expected).
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