Re: [PATCH] x86_64: fix problems due to use of "outb" to port 80 onsome AMD64x2 laptops, etc.

[Alan Cox]

On Sat, 15 Dec 2007 14:27:25 +0100
Ingo Molnar <mingo@xxxxxxx> wrote:

> 
> * Rene Herman <rene.herman@xxxxxxxxx> wrote:
> 
> > The issue is -- how do you safely replace the outb pre-loops_per_jiffy 
> > calibration? I'm currently running with the attached hack (not 
> > submitted, only for 32-bit and discussion) the idea of which might be 
> > the best we can do?
> 
> how about doing a known-NOP chipset cycle? For example:
> 
>   inb(PIC_SLAVE_IMR)

It needs tobe a different chip to the main one (or macrocell anyway) - so
PIC for PIT and vice versa. However since we know 0x80 works for
everything on the planet but this one specifies of laptop which seems to
need a firmware update its a very high risk approach.

Alan
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