On Sat, Jul 19, 2014 at 11:05:33AM +0200, Arnd Bergmann wrote:

On Saturday 19 July 2014 10:41:52 Sam Ravnborg wrote:

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This set:
#define inb_p(addr)     inb(addr)
#define inw_p(addr)     inw(addr)
#define inl_p(addr)     inl(addr)
#define outb_p(x, addr) outb((x), (addr))
#define outw_p(x, addr) outw((x), (addr))
#define outl_p(x, addr) outl((x), (addr))

Should have a comment that say they are deprecated.
Especially the "b" variants still have many users.

Are they? I don't remember ever seeing a reason to deprecate
them. We could perhaps enclose them in #ifdef CONFIG_ISA, but
there may also be some drivers that use the same code for ISA
and PCI, and it doesn't really hurt on PCI.

It is my understanding that inl and inl_p are the same these days.
A quick grep indicate that only m68k define the
_p variant different from the other.
But I failed to find and description of the difference between the
two which is why I assumed they were identical and thus no need for both.

I don't know why m68k needs it, it's really an x86-specific
thing, see slow_down_io() in arch/x86/include/asm/io.h.

I had missed the x86 versions when grepping.
Hmm, and with the macro tricks they play in asm/io.h this
file is not at all grep friendly.

So xxx_p is for pause (or something like that).
This also matches that m68k do some tricks with delay() in the _p variants.
Thanks for the explanation.

	Sam