From: ebiederm@xmission.com (Eric W. Biederman)
   Date: 18 Sep 2002 11:27:34 -0600

   "David S. Miller" [off-list ref] writes:
   
   > {in,out}{b,w,l}() operations have a fixed timing, therefore his
   > results doesn't sound that far off.
   ????
   
   I don't see why they should be.  If it is a pci device the cost should
   the same as a pci memory I/O.  The bus packets are the same.  So things like
   increasing the pci bus speed should make it take less time.

The x86 processor has a well defined timing for executing inb
etc. instructions, the timing is fixed and is independant of the
speed of the PCI bus the device is on.