[Bug 91400] New: Linux >= 3.19 graphics corruption and system crash when running as Xen dom0 with VT-d enabled on Intel Ironlake

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=91400

            Bug ID: 91400
           Summary: Linux >= 3.19 graphics corruption and system crash
                    when running as Xen dom0 with VT-d enabled on Intel
                    Ironlake
           Product: DRI
           Version: unspecified
          Hardware: x86-64 (AMD64)
                OS: Linux (All)
            Status: NEW
          Severity: major
          Priority: medium
         Component: DRM/Intel
          Assignee: intel-gfx-bugs at lists.freedesktop.org
          Reporter: lantw44 at gmail.com
        QA Contact: intel-gfx-bugs at lists.freedesktop.org
                CC: intel-gfx-bugs at lists.freedesktop.org
        Depends on: 90037

Created attachment 117251
  --> https://bugs.freedesktop.org/attachment.cgi?id=117251&action=edit
dmesg

+++ This bug was initially created as a clone of Bug #90037 +++

When I use Linux >= 3.19 as the dom0 kernel of Xen, screen becomes unreadable
after i915 driver is loaded. The screenshot is already posted as an attachment
of another bug: https://bugs.freedesktop.org/attachment.cgi?id=115079. This
screenshot is obtained when the system is in single user mode.

If it continues to boot into graphical mode, a lot of error messages are showed
when the display manager is started. Screen output becomes more broken and the
system crashes after several minutes.

VT-d is automatically enabled by Xen. If VT-d is manually disabled, there is no
graphics problem and the system can run normally.

The bad commit showed by git bisect is
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=47591df

Please see the attached Xen dmesg, Linux dmesg and GPU crash dump.


CPU and GPU:
Intel Core i5 CPU 650 @ 3.20GHz
Intel Ironlake Desktop

Motherboard:
ASUSTeK Computer INC. P7H55D-M EVO

Software:
Xen 4.5.1
Linux 4.2-rc3
Xorg 1.17.2
Wayland 1.7.0
GDM 3.16.2
GNOME Shell 3.16.3


This problem was initially reported as here:
https://bugs.freedesktop.org/show_bug.cgi?id=90037

I sent a message to xen-devel and they thought it should be an i915 problem:
http://lists.xenproject.org/archives/html/xen-devel/2015-06/msg02236.html
http://lists.xenproject.org/archives/html/xen-devel/2015-06/msg02387.html

As I don't know how to fix the problem, I made a workaround in Xen:
http://lists.xenproject.org/archives/html/xen-devel/2015-07/msg03641.html

They also said it is an i915 problem:
http://lists.xenproject.org/archives/html/xen-devel/2015-07/msg03642.html
http://lists.xenproject.org/archives/html/xen-devel/2015-07/msg03723.html



A silimar problem also happens on Linux >= 3.7 without using Xen:
https://bugs.freedesktop.org/show_bug.cgi?id=91127

It was partially fixed in Linux 4.2-rc2:
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=8b572a4



It seems there are some common messages showed by Xen and Linux:

Messages showed by Xen with Linux 4.2-rc3 dom0:
(XEN) [VT-D]DMAR:[DMA Write] Request device [0000:00:02.0] fault addr
73fbff000, iommu reg = ffff82c000203000
(XEN) [VT-D]DMAR: reason 05 - PTE Write access is not set

Messages showed by Linux 4.2-rc2 when not using Xen:
DMAR: DMAR:[DMA Write] Request device [00:02.0] fault addr fde7c000
DMAR:[fault reason 05] PTE Write access is not set

-- 
You are receiving this mail because:
You are the QA Contact for the bug.
You are on the CC list for the bug.
You are the assignee for the bug.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.freedesktop.org/archives/intel-gfx-bugs/attachments/20150720/78b50483/attachment.html>