Hi Maxime, On 17/04/2015 16:32, Maxime Ripard wrote: > On Fri, Apr 17, 2015 at 04:19:22PM +0200, Boris Brezillon wrote: >> Hi Gregory, >> >> On Fri, 17 Apr 2015 15:01:01 +0200 >> Gregory CLEMENT <gregory.clement@xxxxxxxxxxxxxxxxxx> wrote: >> >>> Hi Boris, >>> >>> On 17/04/2015 10:39, Boris Brezillon wrote: >>>> On Fri, 17 Apr 2015 10:33:56 +0200 >>>> Boris Brezillon <boris.brezillon@xxxxxxxxxxxxxxxxxx> wrote: >>>> >>>>> Hi Jason, >>>>> >>>>> On Mon, 13 Apr 2015 20:11:46 +0000 >>>>> Jason Cooper <jason@xxxxxxxxxxxxxx> wrote: >>>>> >>>>>>> >>>>>>>> I'd appreciate if we'd look into it. I understand from on-list and >>>>>>>> off-list discussion that the rewrite was unavoidable. So I'm willing to >>>>>>>> concede that. Giving people time to migrate from old to new while still >>>>>>>> being able to update for other security fixes seems reasonable. >>>>>>> >>>>>>> Jason, what do you think of the approach above? >>>>>> >>>>>> I say keep it simple. We shouldn't use the DT changes to trigger one >>>>>> vice the other. We need to be able to build both, but only load one at >>>>>> a time. If that's anything other than simple to do, then we make it a >>>>>> Kconfig binary choice and move on. >>>>> >>>>> Actually I was planning to handle it with a Kconfig dependency rule >>>>> (NEW_DRIVER depends on !OLD_DRIVER and OLD_DRIVER depends >>>>> on !NEW_DRIVER). >>>>> I don't know how to make it a runtime check without adding new >>>>> compatible strings for the kirkwood, dove and orion platforms, and I'm >>>>> sure sure this is a good idea. >>>> ^ not >>>> >>>>> Do you have any ideas ? >>> >>> You use devm_ioremap_resource() in the new driver, so if the old one >>> is already loaded the memory region will be already hold and the new >>> driver will simply fail during the probe. So for this part it is OK. >> >> I like the idea :-). > > Not really, how do you know which device is going to be probed? For > that matter, it's pretty much random, and you have no control over it. > > Why not just have a choice option, and select which one you want to > enable? Because you can't prevent an user to build a module, then modifying the configuration and building the other module. So even if there is a choice at build time, and I think that it is something expected for the v2, we still need preventing having the both drivers trying accessing the same hardware in the same time. Thanks, Gregory > > Maxime > -- Gregory Clement, Free Electrons Kernel, drivers, real-time and embedded Linux development, consulting, training and support. http://free-electrons.com -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
