On Sun, Jan 20, 2013 at 10:52 PM, Mihai Moldovan ionic@ionic.de wrote:
the patch does work, i.e., it turns off DMAR for the graphics card and alleviates the freezes when loading i915/kms.
However, still seeing random machine freezes with it (being consistent with the behavior I've experienced with intel_iommu=igfx_off).
Thanks for testing, I've just submitted the patch for review. It should included in a -fixes tree soon and the get backported to stable kernels.
The patch + forcing RWBF is working, too. Interestingly, this version didn't randomly freeze yet, after more than 5 hours of uptime! I'll leave the box running until tomorrow to make sure I did stick around long enough.
All those tested kernels were able to handle USB and PCI(e) devices.
I still have to test turning off IOMMU in general and Intel IOMMU specifically. Will probably do this tomorrow.
Please let me know when this works solidly for you, so that I can put it into a real patch and also submit it for inclusion.
Thanks, Daniel