Prefmem of bus 3

ron minnich rminnich at lanl.gov
Fri Mar 5 00:27:01 CET 2004


On Thu, 4 Mar 2004, Yinghai Lu wrote:

> Also according to suggestion from quadrics and amd, it seems that BIOS and
> kernel need to be patched to allow the prefmem region ( after mmio_basek) to
> be put the mtrr as write-back to get the better perfmormance. i.e. 2.5us->1.
> 8us 0-byte ping pong. So may need to change the write_linuxbios_table and
> update the struct mem_reagion.

I don't think the bios should do that. This setting of the mtrr for a 
particular card, on a particular motherboard, with a particular CPU, OS, 
and library, is really not a matter for the BIOS to decide. This is a job 
for /dev/mtrr. 

ron




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