On Sun, Jul 13, 2014 at 09:33:38PM +0200, Richard Weinberger wrote: > Am 13.07.2014 21:22, schrieb Greg Kroah-Hartman: > > On Sun, Jul 13, 2014 at 04:25:06PM +0200, Lars-Peter Clausen wrote: > >> On 07/13/2014 04:03 PM, Richard Weinberger wrote: > >>> Am 13.07.2014 15:56, schrieb Lars-Peter Clausen: > >>>> On 07/13/2014 03:40 PM, Richard Weinberger wrote: > >>>>> Am 13.07.2014 15:26, schrieb Lars-Peter Clausen: > >>>>>> On 07/13/2014 11:45 AM, Richard Weinberger wrote: > >>>>>>> Am 13.07.2014 11:27, schrieb Lennox Wu: > >>>>>>>> As I said before, some configurations don't make sense. > >>>>>>> > >>>>>>> If such a configuration can be achieved using allmod/yesconfig it has to be fixed. > >>>>>>> Chen's fixes seem reasonable as not all architectures support iomem. > >>>>>> > >>>>>> Maybe we should stub out ioremap() and friends when COMPILE_TEST is enabled to avoid these linker errors. That's in my opinion better than turning most of the 'depends on > >>>>>> COMPILE_TEST' into 'depends on COMPILE_TEST && HAS_IOMEM'. The issue comes up quite a lot and it is often overlooked when adding a driver that can be build when COMPILE_TEST is > >>>>>> enabled. > >>>>> > >>>>> And what should this stub do? > >>>>> Except calling BUG()... > >>>> > >>>> return NULL; > >>>> > >>>> It's for compile testing, it's not meant to work at runtime. > >>> > >>> Hm, I really don't like the idea of having a non-working kernel. > >>> IMHO either it should build _and_ run and nothing else. > >>> Greg, what do you think? > >> > >> The kernel will still be working fine and you can run it on a system. The > >> drivers which use ioremap() or similar are probably not instantiated on a > >> system that does not provide HAS_IOMEM. But even if it was the driver should > >> handle ioremap() returning NULL gracefully and abort the driver probe. That > >> said you'll probably not run a kernel that was built with COMPILE_TEST on > >> your real hardware since it contains so many drivers that are completely > >> useless on your hardware. The idea of COMPILE_TEST is to have as much > >> compile test exposure as possible to the code that is enabled by > >> COMPILE_TEST. Stubbing out ioremap() and friends when HAS_IOMEM is not set > >> and COMPILE_TEST is set makes it easier to get there. > > > > I run my kernels with COMPILE_TEST enabled as I need to build test > > things that I don't happen to use. > > > > I like the 'return NULL' option for this, it hits us all the time, might > > as well fix it properly like this so that we don't have to deal with > > Kconfig changes everywhere. > > > > Also put a big "This platform does not support IOMEM" error printk in > > there, so that people have a chance to figure out what is going on if > > they happen to run such a driver on a platform that can't support it. > > Maybe we could add COMPILE_TEST to the version string too? > Just to detect such kernels fast in user bug reports... What kind of bug report are you going to get? -- 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
