Re: [PATCH] x86: use explicit timing delay for pit accesses in kerneland pcspkr driver

From: H. Peter Anvin
Date: Mon Feb 18 2008 - 17:44:21 EST


Rene Herman wrote:

Uhm, I'm not sure I believe that's safe.

The PIT is particularly pissy in this case -- the semantics of the PIT are ill-defined if there hasn't been a PIT clock between two adjacent accesses, so I fully expect that there are chipsets out there which will do very bad things in this case.

Okay. Now that they're isolated, do you have a suggestion for {in,out}b_pit? You say a PIT clock, so do you think we can bounce of the PIT iself in this case after all?

No, I don't think so.

-hpa
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