Cc: Rene Herman <rene.herman@...>, Paul Rolland <rol@...>, H. Peter Anvin <hpa@...>, Krzysztof Halasa <khc@...>, Pavel Machek <pavel@...>, Andi Kleen <andi@...>, David P. Reed <dpreed@...>, <linux-kernel@...>, Thomas Gleixner <tglx@...>, Ingo Molnar <mingo@...>, <rol@...>
The _p variants are a universal fixture, defined as ending with a pause,
but without specifying the duration. (The duration is architecture
specific, mostly zero.) It really isn't a form that should be used in
generic code.
Yes, it's now clear that all of this is so. Regrettably, it's used in
dozens of drivers, most having nothing to do with an ISA/LPC bus.
If it really is specific to the ISA architecture, then it should only be
used in architecture specific code.
I think the solution is to remove it. Replace all _p calls with the
non-_p variant, and add an explicit udelay. Udelay can initially be set
conservatively until it's been properly calibrated, allowing it to be
used during early boot. The good news is that it's only used in a few
dozen drivers, so that actually might be doable. And then, who knows,
maybe Microsoft might have to scratch their corporate heads, trying to
find out how to compete with a suddenly much faster Linux! :-p
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