From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ting-Wei Lan Subject: Kernel panic on Linux 4.1 with intel_iommu=on Date: Wed, 01 Jul 2015 03:32:33 +0800 Message-ID: <1435692753.7564.17.camel@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org List-Id: iommu@lists.linux-foundation.org Hardware: Intel Core i5 CPU 650 @ 3.20GHz Intel Ironlake Desktop In order to use VT-d on this computer, I have to use 'intel_iommu=on intel_iommu=igfx_off' to prevent graphics problems and system crash. This problem happens on Linux 3.7 and later versions, including the latest release, Linux 4.1. I found Intel-IOMMU.txt says I should file a bug if intel_iommu=igfx_off fixes anything. I filed the bug on freedesktop -> DRI -> DRM/Intel. https://bugs.freedesktop.org/show_bug.cgi?id=91127 After I applied this patch, I no longer saw graphics problems, and Xorg and Wayland can be successfully started without intel_iommu=igfx_off. https://bugs.freedesktop.org/show_bug.cgi?id=91127#c6 However, after using the system for about one hour, the system crashed and printed some messages on the serial console. I have to press the reset button to reboot the machine. https://bugs.freedesktop.org/show_bug.cgi?id=91127#c8 Can anyone here help us resolve this problem?