Re: __bad_udelay in 2.2.18pre15

From: Alan Cox (alan@lxorguk.ukuu.org.uk)
Date: Wed Oct 11 2000 - 11:27:26 EST


> >> #define udelay(n) (__builtin_constant_p(n) ? \
> >> ((n) > 20000 ? __bad_udelay() : __const_udelay((n) *
> >> 0x10c6ul)) : \
> >> __udelay(n))
> >>
> >> ...
> >> It seems __bad_udelay is not defined anywhere in the kernel source.
> >
> >Correct. Its a compile time error trap
>
> Well, at first, I wanted to implement it the same way on PPC. However, it
> dies on all occurences where udelay is called with a non-constant expression.

__builtin_constant_p means non constant expressions will always call udelay

> I spotted this case in a few PPC specific stuffs (fixable), but also in
> the sys_nanosleep code, and in the de4x5 driver.

I'll check these two

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