From mboxrd@z Thu Jan 1 00:00:00 1970 From: Troy Heber Date: Fri, 18 Aug 2006 13:55:16 +0000 Subject: Re: [Fastboot] [patch 3/5] git-ia64 versus genirq Message-Id: <20060818135515.GA25785@pc.troyhebe> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-ia64@vger.kernel.org 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