Re: [GIT PULL 3/6] ARM: SoC driver updates for 5.1

From: Russell King - ARM Linux admin
Date: Wed Mar 06 2019 - 13:16:19 EST


On Wed, Mar 06, 2019 at 10:09:28AM -0800, Linus Torvalds wrote:
> On Wed, Mar 6, 2019 at 7:34 AM Arnd Bergmann <arnd@xxxxxxxx> wrote:
> >
> > git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc.git tags/armsoc-drivers
>
> This caused a surprising number of kernel file rebuilds for me, and
> the reason was
>
> > include/linux/mod_devicetable.h | 9 +
>
> It turns out that the above is indirectly included from a _lot_ of
> code device header files.
>
> The reason seems to be the various 'struct *_device_id' declarations,
> that then all the different header files want.
>
> So a tiny change in an oddball header file causes a lot of recompiles.
>
> Oh well. I don't know if there is anything to be done, but I did react
> to how some surprising changes cause a lot of build activity, and it's
> not always obvious.

Would it be worth splitting up mod_devicetable.h and having drivers
include just the bus-specific device table header(s) that the driver
requires?

--
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