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. 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
