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From:   Mauro Carvalho Chehab <mchehab@kernel.org>
Cc:     Chris Wilson <chris.p.wilson@intel.com>,
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Subject: [PATCH v3 4/6] drm/i915/gt: Skip TLB invalidations once wedged
Date:   Wed, 27 Jul 2022 14:29:54 +0200
Message-Id: <5aa86564b9ec5fe7fe605c1dd7de76855401ed73.1658924372.git.mchehab@kernel.org>
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From: Chris Wilson <chris.p.wilson@intel.com>

Skip all further TLB invalidations once the device is wedged and
had been reset, as, on such cases, it can no longer process instructions
on the GPU and the user no longer has access to the TLB's in each engine.

So, an attempt to do a TLB cache invalidation will produce a timeout.

That helps to reduce the performance regression introduced by TLB
invalidate logic.

Cc: stable@vger.kernel.org
Fixes: 7938d61591d3 ("drm/i915: Flush TLBs before releasing backing store")
Signed-off-by: Chris Wilson <chris.p.wilson@intel.com>
Cc: Fei Yang <fei.yang@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Andi Shyti <andi.shyti@linux.intel.com>
Acked-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
---

To avoid mailbombing on a large number of people, only mailing lists were C/C on the cover.
See [PATCH v3 0/6] at: https://lore.kernel.org/all/cover.1658924372.git.mchehab@kernel.org/

 drivers/gpu/drm/i915/gt/intel_gt.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/i915/gt/intel_gt.c b/drivers/gpu/drm/i915/gt/intel_gt.c
index 1d84418e8676..5c55a90672f4 100644
--- a/drivers/gpu/drm/i915/gt/intel_gt.c
+++ b/drivers/gpu/drm/i915/gt/intel_gt.c
@@ -934,6 +934,9 @@ void intel_gt_invalidate_tlbs(struct intel_gt *gt)
 	if (I915_SELFTEST_ONLY(gt->awake == -ENODEV))
 		return;
 
+	if (intel_gt_is_wedged(gt))
+		return;
+
 	if (GRAPHICS_VER(i915) == 12) {
 		regs = gen12_regs;
 		num = ARRAY_SIZE(gen12_regs);
-- 
2.36.1