Ubuntu
xserver-xorg-video-intel package

  1. Bug #946311
  2. Comment #137

Comment 137 for bug 946311

Revision history for this message
In , Imre Deak (ideak) wrote :

(In reply to comment #115)
> Yes, it works.

Thanks, it narrows it down. I looked through the Intel HW IOMMU code and haven't found anything obvious that could explain this.

OTOH, looking again at the dmesg with the crash (dmesg-3.10.0-rc6-00406-g73bc88c) I can't see the HW IOMMU being enabled. I'd expect "PCI-DMA: Intel(R) Virtualization Technology for Directed I/O". Instead I see SWIOTLB being enabled there. But if you are using SWIOTLB I don't understand why igfx_off makes any difference. Also the workaround in my patch should be already active for SWIOTLB, so that shouldn't make any difference either. Could you check if you had that workaround in your test kernel (1625e7e549 - "drm/i915: make compact dma scatter lists creation work with SWIOTLB backend")?