From: Neil Horman Date: Tue, 16 Apr 2013 20:38:32 +0000 (-0400) Subject: iommu/vt-d: add quirk for broken interrupt remapping on 55XX chipsets X-Git-Tag: omap-for-v3.10/dt-fixes-for-merge-window~25^2~4 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=03bbcb2e7e292838bb0244f5a7816d194c911d62;p=pandora-kernel.git iommu/vt-d: add quirk for broken interrupt remapping on 55XX chipsets A few years back intel published a spec update: http://www.intel.com/content/dam/doc/specification-update/5520-and-5500-chipset-ioh-specification-update.pdf For the 5520 and 5500 chipsets which contained an errata (specificially errata 53), which noted that these chipsets can't properly do interrupt remapping, and as a result the recommend that interrupt remapping be disabled in bios. While many vendors have a bios update to do exactly that, not all do, and of course not all users update their bios to a level that corrects the problem. As a result, occasionally interrupts can arrive at a cpu even after affinity for that interrupt has be moved, leading to lost or spurrious interrupts (usually characterized by the message: kernel: do_IRQ: 7.71 No irq handler for vector (irq -1) There have been several incidents recently of people seeing this error, and investigation has shown that they have system for which their BIOS level is such that this feature was not properly turned off. As such, it would be good to give them a reminder that their systems are vulnurable to this problem. For details of those that reported the problem, please see: https://bugzilla.redhat.com/show_bug.cgi?id=887006 [ Joerg: Removed CONFIG_IRQ_REMAP ifdef from early-quirks.c ] Signed-off-by: Neil Horman CC: Prarit Bhargava CC: Don Zickus CC: Don Dutile CC: Bjorn Helgaas CC: Asit Mallick CC: David Woodhouse CC: linux-pci@vger.kernel.org CC: Joerg Roedel CC: Konrad Rzeszutek Wilk CC: Arkadiusz Miśkiewicz Signed-off-by: Joerg Roedel --- Reading git-diff-tree failed