Re: [PATCH] x86-64: disable the GART before allocate aperture

[Yinghai Lu <Yinghai.Lu@Sun.COM>]

Andi Kleen wrote:
> On Saturday 23 June 2007 00:19:51 Alan Cox wrote:
> The kdump kernel should be normally all <4GB anyways. You won't
> need any IOMMU for its IO unless you O_DIRECT/sendfile out of /proc/kcore.
> Just don't do that (but I suspect it won't work anyways)
> 
> If it's not then swiotlb will also not work because it won't get 
> any memory <4GB.
> 
> But I doubt this was YH's problem - the panic kernel memory
> is always reserved and there shouldn't be any ongoing DMAs in this
> area anyways. And what happens outside the kdump kernel shouldn't matter.
> 
> I suspect he rather saw problems with non kdump kexec where we
> can just shut down the GART properly beforehand.

current I only test kexec only. So clean shut GART in first kernel will help.

where is hook for shutdown? add one in dma_ops?

YH