[Bug 87279] Intel GM45 graphics glitches with Kernel 3.18

bugzilla-daemon at freedesktop.org bugzilla-daemon at freedesktop.org
Sun Dec 14 20:54:58 PST 2014


https://bugs.freedesktop.org/show_bug.cgi?id=87279

--- Comment #7 from Ugis Germanis <ugis.germanis at gmail.com> ---
After long night of bisecting, I've found the commit that seem to fix this bug
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d472fcc8379c062bd56a3876fc6ef22258f14a91 is the first bad commit
commit d472fcc8379c062bd56a3876fc6ef22258f14a91
Author: Daniel Vetter <daniel.vetter at ffwll.ch>
Date:   Mon Nov 24 11:12:42 2014 +0100

    drm/i915: Disallow pin ioctl completely for kms drivers

    The problem here is that SNA pins batchbuffers to etch out a bit more
    performance. Iirc it started out as a w/a for i830M (which we've
    implemented in the kernel since a long time already). The problem is
    that the pin ioctl wasn't added in

    commit d23db88c3ab233daed18709e3a24d6c95344117f
    Author: Chris Wilson <chris at chris-wilson.co.uk>
    Date:   Fri May 23 08:48:08 2014 +0200

        drm/i915: Prevent negative relocation deltas from wrapping

    Fix this by simply disallowing pinning from userspace so that the
    kernel is in full control of batch placement again. Especially since
    distros are moving towards running X as non-root, so most users won't
    even be able to see any benefits.

    UMS support is dead now, but we need this minimal patch for
    backporting. Follow-up patch will remove the pin ioctl code
    completely.

    Note to backporters: You must have both

    commit b45305fce5bb1abec263fcff9d81ebecd6306ede
    Author: Daniel Vetter <daniel.vetter at ffwll.ch>
    Date:   Mon Dec 17 16:21:27 2012 +0100

        drm/i915: Implement workaround for broken CS tlb on i830/845

    which laned in 3.8 and

    commit c4d69da167fa967749aeb70bc0e94a457e5d00c1
    Author: Chris Wilson <chris at chris-wilson.co.uk>
    Date:   Mon Sep 8 14:25:41 2014 +0100

        drm/i915: Evict CS TLBs between batches

    which is also marked cc: stable. Otherwise this could introduce a
    regression by disabling the userspace w/a without the kernel w/a being
    fully functional on i830/45.

    References: https://bugs.freedesktop.org/show_bug.cgi?id=76554#c116
    Cc: stable at vger.kernel.org # requires c4d69da167fa967749a and v3.8
    Cc: Chris Wilson <chris at chris-wilson.co.uk>
    Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>

:040000 040000 4345ff9fc3b775222a59890caf35c033b5a5bacf
c8a157f364e4e0490b6bf1df0321a24bfd069f2e M      drivers

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