[PATCH 4.12 05/41] drm/i915: Perform an invalidate prior to executing golden renderstate

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

4.12-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Chris Wilson <chris@chris-wilson.co.uk>

commit a0125a932e917cb507b682cb66645efdca1f8cab upstream.

As we may have just bound the renderstate into the GGTT for execution, we
need to ensure that the GTT TLB are also flushed.

On snb-gt2, this would cause a random GPU hang at the start of a new
context (e.g. boot) and on snb-gt1, it was causing the renderstate batch
to take ~10s. It was the GPU hang that revealed the truth, as the CS
gleefully executed beyond the end of the golden renderstate batch, a good
indicator for a GTT TLB miss.

Fixes: 20fe17aa52dc ("drm/i915: Remove redundant TLB invalidate on switching contexts")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20170808131904.1385-1-chris@chris-wilson.co.uk
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: <drm-intel-fixes@lists.freedesktop.org> # v4.12-rc1+
(cherry picked from commit 802673d66f8a6ded5d2689d597853c7bb3a70163)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/gpu/drm/i915/i915_gem_render_state.c |    4 ++++
 1 file changed, 4 insertions(+)

--- a/drivers/gpu/drm/i915/i915_gem_render_state.c
+++ b/drivers/gpu/drm/i915/i915_gem_render_state.c
@@ -242,6 +242,10 @@ int i915_gem_render_state_emit(struct dr
 			goto err_unpin;
 	}
 
+	ret = req->engine->emit_flush(req, EMIT_INVALIDATE);
+	if (ret)
+		goto err_unpin;
+
 	ret = req->engine->emit_bb_start(req,
 					 so->batch_offset, so->batch_size,
 					 I915_DISPATCH_SECURE);