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

Aravind Gopalakrishnan
2015-04-02T16:23:27Z

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.