Re: [PATCH] x86, aperture: Check for GART before accessing GART registers

From: Aravind Gopalakrishnan
Date: Thu Apr 02 2015 - 12:23:43 EST


On 4/2/2015 11:06 AM, Ingo Molnar wrote:


We get "AGP:" messages on kernel logs like this-
[ 0.000000] AGP: Node 0: aperture [bus addr 0x00000000-0x01ffffff] (32MB)
[ 0.000000] AGP: Your BIOS doesn't leave a aperture memory hole
[ 0.000000] AGP: Please enable the IOMMU option in the BIOS setup
[ 0.000000] AGP: This costs you 64MB of RAM
[ 0.000000] AGP: Mapping aperture over RAM [mem 0xd4000000-0xd7ffffff]
(65536KB)

These are just noise on processors which have no GART.
agreed.

We can avoid calling allocate_aperture() and would not have to
memblock_reserve() 64MB of RAM.
Also, we can avoid having to loop through all PCI buses, devices (twice)
searching for AGP bridge if we bail out early.
Makes sense. Mind adding this info to the changelog and resend?



Sure, will do that and resend.

Thanks,
-Aravind.
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