From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Tue, 2 Jan 2018 19:25:00 +0000
Subject: drm/i915: Assert we do not try to wait on an invalid seqno
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Git-commit: c68ce69910e3b292afc138e12725399d3b0fb347
Patch-mainline: v4.17-rc1
References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166

We should never insert the invalid seqno into the wait tree, so assert
we do not.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Michał Winiarski <michal.winiarski@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180102192500.20364-1-chris@chris-wilson.co.uk

Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 drivers/gpu/drm/i915/intel_breadcrumbs.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/drivers/gpu/drm/i915/intel_breadcrumbs.c
+++ b/drivers/gpu/drm/i915/intel_breadcrumbs.c
@@ -385,6 +385,8 @@ static bool __intel_engine_add_wait(stru
 	bool first, armed;
 	u32 seqno;
 
+	GEM_BUG_ON(!wait->seqno);
+
 	/* Insert the request into the retirement ordered list
 	 * of waiters by walking the rbtree. If we are the oldest
 	 * seqno in the tree (the first to be retired), then