Messages in this thread | | | Date | Tue, 8 Jan 2008 01:58:36 +0000 | From | Alan Cox <> | Subject | Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override. |
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> The PIT usage for calibrating the delay loop can be moderated, if need > by, by using the PC BIOS which by definition uses the PIT correctly it > its int 15 function 83 call.. Just do it before coming up in a state > where the PC BIOS int 15h calls no longer work. I gave code to do this > in a much earlier message.
And as I've said before we don't know if we have a PC BIOS. If we are running from a kexec or on a Macintoy with EFI or an Xbox we may not.
As per previous discussions for the PIT we can simply guess a safe initial udelay value and then tune the real one.
Alan
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