drm/i915: Perform an invalidate prior to executing golden renderstate

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>
Cc: stable@vger.kernel.org
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>

diff --git a/drivers/gpu/drm/i915/i915_gem_render_state.c b/drivers/gpu/drm/i915/i915_gem_render_state.c
index 7032c542a9b1d007c4bc69e328db040b88efc15d..4dd4c2159a92e26d91fd98e560c587a91b964e48 100644 (file)
--- 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 drm_i915_gem_request *req)
                        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);