Dne 17.6.2013 22:05, Jiri Slaby napsal(a): > On 05/23/2013 05:09 AM, Jeff Mahoney wrote: >> On 5/22/13 10:23 PM, Greg Kroah-Hartman wrote: >>> On Wed, May 22, 2013 at 11:18:46AM +0200, Jiri Slaby wrote: >>>> Some drivers can be built on more platforms than they run on. This >>>> causes users and distributors packaging burden when they have to >>>> manually deselect some drivers from their allmodconfigs. Or sometimes >>>> it is even impossible to disable the drivers without patching the >>>> kernel. >>>> >>>> Introduce a new config option COMPILE_TEST and make all those drivers >>>> to depend on the platform they run on, or on the COMPILE_TEST option. >>>> Now, when users/distributors choose COMPILE_TEST=n they will not have >>>> the drivers in their allmodconfig setups, but developers still can >>>> compile-test them with COMPILE_TEST=y. >>> >>> I understand the urge, and it's getting hard for distros to handle these >>> drivers that just don't work on other architectures, but it's really >>> valuable to ensure that they build properly, for those of us that don't >>> have many/any cross compilers set up. > > But this is exactly what COMPILE_TEST will give us when set to "y", or > am I missing something? > >>>> Now the drivers where we use this new option: >>>> * PTP_1588_CLOCK_PCH: The PCH EG20T is only compatible with Intel Atom >>>> processors so it should depend on x86. >>>> * FB_GEODE: Geode is 32-bit only so only enable it for X86_32. >>>> * USB_CHIPIDEA_IMX: The OF_DEVICE dependency will be met on powerpc >>>> systems -- which do not actually support the hardware via that >>>> method. >>> >>> This seems ripe to start to get really messy, really quickly. Shouldn't >>> "default configs" handle if this "should" be enabled for a platform or >>> not, and let the rest of us just build them with no problems? >> >> If every time a new Kconfig option is added, corresponding default >> config updates come with it, sure. I just don't see that happening, >> especially when it can be done much more clearly in the Kconfig while >> the developer is writing the driver. >> >>> What problems is this causing you? Are you running out of space in >>> kernel packages with drivers that will never be actually used? >> >> Wasted build resources. Wasted disk space on /every/ system the kernel >> package is installed on. We're all trying to pare down the kernel >> packages to eliminate wasted space and doing it manually means a bunch >> of research, sometimes with incorrect assumptions about the results, >> needs to be done by someone not usually associated with that code. That >> research gets repeated by people maintaining kernel packages for pretty >> much every distro. > > I second all the above. > >>>> +config COMPILE_TEST >>>> + bool "Compile also drivers which will not load" if EXPERT >>> >>> EXPERT is getting to be the "let's hide it here" option, isn't it... >>> >>> I don't know, if no one else strongly objects, I can be convinced that >>> this is needed, but so far, I don't see why it really is, or what this >>> is going to help with. >> >> I'm not convinced adding a || COMPILE_TEST option to every driver that >> may be arch specific is the best way to go either. Perhaps adding a new >> Kconfig verb called "archdepends on" or something that will evaluate as >> true if COMPILE_TEST is enabled but will evaluate the conditional if >> not. *waves hands* > > Sam Ravnborg (the kconfig ex-maintainer) once wrote that he doesn't want > to extend the kconfig language for this purpose (which I support). That > a config option is fine and sufficient in this case [1]. Except he > called the config option "SHOW_ALL_DRIVERS". Adding the current > maintainer to CCs ;). I agree with Sam. 'depends on XY || COMPILE_TEST' is quite self-explanatory. And even if it's not, you can look up the help text for COMPILE_TEST. With "archdepends on" or "available on", you need to know what to look for to override the dependency. Michal -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
