Re: PCI card initialisation at boot

From: H. Peter Anvin
Date: Sun Nov 11 2007 - 19:22:39 EST


Matt Domsch wrote:
On Sun, Nov 11, 2007 at 04:46:44PM +0000, Alan Cox wrote:
Linux by default uses the BIOS resource assignments. It doesn't know
where those came from other than "the BIOS".

Slightly tangential, but I'm starting to hear requests to have the OS
re-assign resources when it might make better sense. For example, if
you have a graphics card with a 1GB memory allocation, the BIOS may
assign it into address ranges below 4GB because it doesn't know
if the OS will be 32-bit or 64-bit capable. But, it would be
beneficial to have it located above 4GB, and to fill in the (new) hole
below 4GB with RAM. Linux right now doesn't have a way to do this.
It will assign resources for cards that the BIOS left unassigned, but
won't intentionally move resources.


Not really. If the OS is 64-bit capable, it can just use the RAM above 4 GB.

-hpa
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