From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Cooper Subject: Re: [PATCH] VT-d: add iommu=igfx_off option to workaround graphics issues Date: Mon, 20 Jul 2015 09:27:13 +0100 Message-ID: <55ACB0E1.6000505@citrix.com> References: <1437159952-4134-1-git-send-email-lantw44@gmail.com> <55ABC817.5030601@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <55ABC817.5030601@citrix.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Julien Grall , Ting-Wei Lan , xen-devel@lists.xen.org Cc: Yang Zhang , Kevin Tian , Jan Beulich List-Id: xen-devel@lists.xenproject.org On 19/07/2015 16:53, Julien Grall wrote: > Hi, > > On 17/07/2015 20:05, Ting-Wei Lan wrote: >> When using Linux >= 3.19 (commit 47591df) as dom0 on some Intel Ironlake >> devices, It is possible to encounter graphics issues that make screen >> unreadable or crash the system. It was reported in freedesktop bugzilla: >> >> https://bugs.freedesktop.org/show_bug.cgi?id=90037 >> >> As we still cannot find a proper fix for this problem, this patch adds >> iommu=igfx_off option that is similar to Linux intel_iommu=igfx_off for >> users to manually workaround the problem. > > I would prefer to see the introduction of intel_iommu parameter in the > vtd code rather than extending again the iommu parameter with intel > specific options in the common code which is both for ARM and x86. Having the parsing for this option inside some x86 ifdefary, fine, but lets not have multiple iommu= options. It is hard enough for people to drive one option (as people routinely get Xen and Linux command line options mixed up). ~Andrew