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* Re: [Fastboot] [patch 3/5] git-ia64 versus genirq
@ 2006-08-18 13:55 Troy Heber
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From: Troy Heber @ 2006-08-18 13:55 UTC (permalink / raw)
  To: linux-ia64

On 08/18/06 08:48, Zou, Nanhai wrote:
> Hi Horms,
> 	I have little knowledge of the code inside CONFIG_IA64_HP_ZX1....
> I think it stop's IOMMU controller on some HP boxes.

Yes, the code is designed to shutdown the IOMMU. The problem we're
seeing is if there are sill in-flight DMA transfers happening when we
shutdown the IOMMU an MCA will occur.

Ring now we're working on a different approach, rather than shutting
down the IOMMU completely, we're going to try to update all of the
valid pdir entries to point to a single pre-alloced page. This should
safely control all of devices with out having to shutdown the IOMMU.

> Aziz told me it is necessary to have this code to start up the second kernel.

I haven't had a chance to speak with Khalid about this approach. I'm
hoping to catch him today.

Troy

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2006-08-18 13:55 [Fastboot] [patch 3/5] git-ia64 versus genirq Troy Heber

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