Re: [ath9k-devel] [PATCH 1/3] ath9k: Fix build error on ARM

On Tue, 2014-02-04 at 19:40 +0100, Arnd Bergmann wrote:

On Tuesday 04 February 2014 08:36:36 Joe Perches wrote:

quoted

On Tue, 2014-02-04 at 08:03 +0100, Holger Schurig wrote:

quoted

Joe, look in linux/arch/arm/include/asm/delay.h. The macro udelay
cannot handle large values because of lost-of-precision.

IMHO udelay on ARM is broken, because it also cannot work with fast
ARM processors (where bogomips >= 3355, which is in sight now). It's
just not broken enought that someone did something against it ...   so
the current kludge is good enought.

Maybe something like this would be better?

I actually like the fact that we get link errors for insane 'udelay'
times.

For static values yes, for computed values no.

This emits a warning/dump_stack on the non-static
values.  It could also emit some similar #warning
on static values > insane too.