[Xen-devel] Mixed results -- VGA Passthrough with Intel 82Q35 IGD

[Jason Sonnek <jsonnek@xxxxxxxxx>]

I have two workstations with Intel 82Q35 Integrated Graphics. The
first is a Dell Optiplex 755 (Intel Core 2 Duo, latest Dell BIOS); the
second is a custom-built machine (Intel Core 2 Quad Q9550, Intel
DQ35JO motherboard, latest Intel BIOS rev. 1143). VGA Passthrough to a
Windows 7 guest works flawlessly on the former. Using the exact same
Xen/Dom0/DomU configuration on the latter, the monitor flickers when
the guest is started and then goes blank. The monitor remains powered
on while the guest is running, suggesting it is receiving some sort of
signal, but no pixels are ever illuminated.

I'm running OpenSUSE 11.3 in Dom0, along with the Xen 4.0.0 package
distributed by SuSE. I've also tried OpenSUSE 11.4 in Dom0 with the
Xen 4.0.2 package; same result in both cases. VT-d is enabled on both
machines, and PCI passthrough of other devices works correctly on both
workstations. With the exception of the memory ranges assigned to the
two IGD devices, the messages emitted in the QEMU and xend logs on
both workstations are more or less identical. I've tried updating the
BIOS to various revs on the non-working machine. Using 'iommu=verbose'
on the Xen command-line, I don't see anything in the ring buffer that
would suggest a problem.

Any suggestions on how I could further debug this issue? Below I've
included hwinfo for the two IGD devices. I'd be happy to attach other
logs if they would help.

Thanks!

Jason


Working 82Q35:

17: PCI 02.0: 0300 VGA compatible controller (VGA)
  [Created at pci.318]
  Unique ID: _Znp.D6lJTogQStC
  SysFS ID: /devices/pci0000:00/0000:00:02.0
  SysFS BusID: 0000:00:02.0
  Hardware Class: graphics card
  Model: "Dell OptiPlex 755"
  Vendor: pci 0x8086 "Intel Corporation"
  Device: pci 0x29b2 "Q35"
  SubVendor: pci 0x1028 "Dell"
  SubDevice: pci 0x0211 "OptiPlex 755"
  Revision: 0x02
  Driver: "pciback"
  Driver Modules: "pciback", "pciback"
  Memory Range: 0xfea00000-0xfea7ffff (rw,non-prefetchable)
  I/O Ports: 0xec90-0xec97 (rw)
  Memory Range: 0xd0000000-0xdfffffff (ro,non-prefetchable)
  Memory Range: 0xfeb00000-0xfebfffff (rw,non-prefetchable)
  IRQ: 16 (30 events)
  I/O Ports: 0x3c0-0x3df (rw)
  Module Alias: "pci:v00008086d000029B2sv00001028sd00000211bc03sc00i00"
  Driver Info #0:
    XFree86 v4 Server Module: intel
  Driver Info #1:
    XFree86 v4 Server Module: intel
    3D Support: yes
    Extensions: dri
  Config Status: cfg=new, avail=yes, need=no, active=unknown

18: PCI 02.1: 0380 Display controller
  [Created at pci.318]
  Unique ID: ruGf.kY6yMez4kU2
  SysFS ID: /devices/pci0000:00/0000:00:02.1
  SysFS BusID: 0000:00:02.1
  Hardware Class: graphics card
  Model: "Dell OptiPlex 755"
  Vendor: pci 0x8086 "Intel Corporation"
  Device: pci 0x29b3 "82Q35 Express Integrated Graphics Controller"
  SubVendor: pci 0x1028 "Dell"
  SubDevice: pci 0x0211 "OptiPlex 755"
  Revision: 0x02
  Driver: "pciback"
  Driver Modules: "pciback", "pciback"
  Memory Range: 0xfea80000-0xfeafffff (rw,non-prefetchable)
  Module Alias: "pci:v00008086d000029B3sv00001028sd00000211bc03sc80i00"
  Config Status: cfg=new, avail=yes, need=no, active=unknown



Non-working 82Q35:


15: PCI 02.0: 0300 VGA compatible controller (VGA)
  [Created at pci.318]
  Unique ID: _Znp.9oGqrtGx1Y7
  SysFS ID: /devices/pci0000:00/0000:00:02.0
  SysFS BusID: 0000:00:02.0
  Hardware Class: graphics card
  Model: "Intel Q35"
  Vendor: pci 0x8086 "Intel Corporation"
  Device: pci 0x29b2 "Q35"
  SubVendor: pci 0x8086 "Intel Corporation"
  SubDevice: pci 0x4f4a
  Revision: 0x02
  Driver: "pciback"
  Driver Modules: "pciback", "pciback"
  Memory Range: 0xe0380000-0xe03fffff (rw,non-prefetchable,disabled)
  I/O Ports: 0x3458-0x345f (rw,disabled)
  Memory Range: 0xd0000000-0xdfffffff (ro,non-prefetchable,disabled)
  Memory Range: 0xe0200000-0xe02fffff (rw,non-prefetchable,disabled)
  IRQ: 16 (no events)
  I/O Ports: 0x3c0-0x3df (rw)
  Module Alias: "pci:v00008086d000029B2sv00008086sd00004F4Abc03sc00i00"
  Driver Info #0:
    XFree86 v4 Server Module: intel
  Driver Info #1:
    XFree86 v4 Server Module: intel
    3D Support: yes
    Extensions: dri
  Config Status: cfg=new, avail=yes, need=no, active=unknown

16: PCI 02.1: 0380 Display controller
  [Created at pci.318]
  Unique ID: ruGf.gEeSljZbJ9D
  SysFS ID: /devices/pci0000:00/0000:00:02.1
  SysFS BusID: 0000:00:02.1
  Hardware Class: graphics card
  Model: "Intel 82Q35 Express Integrated Graphics Controller"
  Vendor: pci 0x8086 "Intel Corporation"
  Device: pci 0x29b3 "82Q35 Express Integrated Graphics Controller"
  SubVendor: pci 0x8086 "Intel Corporation"
  SubDevice: pci 0x4f4a
  Revision: 0x02
  Driver: "pciback"
  Driver Modules: "pciback", "pciback"
  Memory Range: 0xe0300000-0xe037ffff (rw,non-prefetchable)
  Module Alias: "pci:v00008086d000029B3sv00008086sd00004F4Abc03sc80i00"
  Config Status: cfg=new, avail=yes, need=no, active=unknown

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