Re: RFC: outb 0x80 in inb_p, outb_p harmful on some modern AMD64 with MCP51 laptops

Pavel Machek
2007-12-11T19:16:27Z

Hi!

>> Anyways it looks like the discussion here is going in a
>> a loop. I had hoped David would post his test results with
>> another port so that we know for sure that the bus aborts (and not port
>> 80) is the problem on his box. But it looks like
>> he doesn't want to do this. Still removing the bus aborts
>> is probably the correct way to go forward.
>
> Yes, I do also still want to know that. David (Reed)?
>
>> Only needs a patch now. If nobody beats me to it i'll
>> add one later to my tree.
>
> Pavel Machek already posted one. His udelay(8) wants to be less -- 1 or "to
> be safe" perhaps 2.
>
> http://lkml.org/lkml/2007/12/9/131

2 at least; that's how long outb(0x80) takes on one of my
machines. Actually, ISA can go down to 4MHz, so maybe we should be
using 4 usec.... but I guess I'm paranoid here.
Pavel
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