On Fri, Apr 08, 2016 at 11:09:22AM -0400, William Breathitt Gray wrote: > On Fri, Apr 08, 2016 at 06:18:09AM -0700, Guenter Roeck wrote: > > From the context, arm and mips use "select ISA". For those, adding and > >auto-selecting ISA_BUS would make sense. For the remaining architectures > >you could simply add "config ISA_BUS". I would suggest to update default > >configurations, though. > > > >There is also "um", for which you effectively disabled ISA support > >as far as I can see. You might want to look into that as well. > > > >> My avoidance of making ISA a selection of ISA_BUS is the possibility of > >> an invalid configuration: a user may initially enable ISA_BUS, then > >> later disable ISA, resulting in ISA_BUS remaining enabled without ISA > >> selected. > >> > >Does that even make sense ? Not sure I understand why you don't just > >select ISA_BUS if ISA is selected. That would also be backward compatible > >and avoid the problem I was concerned about. > > I feel now that the introduction of the ISA_BUS option may the wrong > approach to resolve lack of ISA support for the X86_64 architecture; > adding ISA_BUS depends or selects through various Kconfigs would simply > obfuscate the ISA option. The true issue is that various driver > configs are assuming X86_32 architecture when they depend on the ISA > option, but the ISA bus does not require an X86_32 architecture. > > The proper resolution then is to remove the misguided ISA_BUS option and > move the X86_32 dependency to the relevant drivers configs explicitly. > A grep for isa_register_driver calls within the kernel reveals that only > a few drivers explicitly use it. It should be trivial to create a patch > to add the explicit X86_32 dependency to the relevant drivers, so I will > submit one soon when I get the time to decouple X86_32 from the ISA > config option. > That might be tricky: At least some if not many of those drivers are expected to run on non-X86 architectures, and thus don't really depend on X86_32 (possibly some depend on 32 bit - I didn't check). I count 44 calls to isa_register_driver() in the current mainline. Not sure if this counts as "only a few drivers". Thanks, Guenter > Once ISA is freed from the X86_32 dependency, I will simply use it > instead of ISA_BUS, and rebase this patchset for version 2. > > >> As a side note, should the dummy isa_register_driver return 0? Would it > >> be more appropriate for it to return an error code to indicate lack of > >> support for ISA, rather than silently fail? > >> > >One should think so. > > > >Thanks, > >Guenter > > > > I'll submit a separate patch for this as well then. > > William Breathitt Gray > -- > To unsubscribe from this list: send the line "unsubscribe linux-watchdog" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
