[Bug 60530] Garbage displayed after resume from suspend to RAM

[bugzilla-daemon at bugzilla.kernel.org]

https://bugzilla.kernel.org/show_bug.cgi?id=60530

--- Comment #50 from Daniel Vetter <daniel at ffwll.ch> ---
3.10.5 should have the fix:

commit 19a280cac37e30243023a7f53651504a135ac960
Author: Daniel Vetter <daniel.vetter at ffwll.ch>
Date:   Wed Jul 17 14:51:28 2013 +0200

    drm/i915: correctly restore fences with objects attached

    commit 94a335dba34ff47cad3d6d0c29b452d43a1be3c8 upstream.

    To avoid stalls we delay tiling changes and especially hold of
    committing the new fence state for as long as possible.
    Synchronization points are in the execbuf code and in our gtt fault
    handler.

    Unfortunately we've missed that tricky detail when adding proper fence
    restore code in

    commit 19b2dbde5732170a03bd82cc8bd442cf88d856f7
    Author: Chris Wilson <chris at chris-wilson.co.uk>
    Date:   Wed Jun 12 10:15:12 2013 +0100

        drm/i915: Restore fences after resume and GPU resets

    The result was that we've restored fences for objects with no tiling,
    since the object<->fence link still existed after resume. Now that
    wouldn't have been too bad since any subsequent access would have
    fixed things up, but if we've changed from tiled to untiled real havoc
    happened:

    The tiling stride is stored -1 in the fence register, so a stride of 0
    resulted in all 1s in the top 32bits, and so a completely bogus fence
    spanning everything from the start of the object to the top of the
    GTT. The tell-tale in the register dumps looks like:

                     FENCE START 2: 0x0214d001
                     FENCE END 2: 0xfffff3ff

    Bit 11 isn't set since the hw doesn't store it, even when writing all
    1s (at least on my snb here).

    To prevent such a gaffle in the future add a sanity check for fences
    with an untiled object attached in i915_gem_write_fence.

    v2: Fix the WARN, spotted by Chris.

    v3: Trying to reuse get_fences looked ugly and obfuscated the code.
    Instead reuse update_fence and to make it really dtrt also move the
    fence dirty state clearing into update_fence.

    Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=60530
    Cc: Chris Wilson <chris at chris-wilson.co.uk>
    Cc: Stéphane Marchesin <marcheu at chromium.org>
    Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>
    Tested-by: Matthew Garrett <matthew.garrett at nebula.com>
    Tested-by: Björn Bidar <theodorstormgrade at gmail.com>
    Signed-off-by: Daniel Vetter <daniel.vetter at ffwll.ch>
    Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>

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