From 3bd639f62d0654e3de953fa4f4313019eda86319 Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Sun, 29 Dec 2019 18:31:48 +0000
Subject: drm/i915/gt: Avoid using tag 0 for the very first submission
Git-commit: 7b02b23e5dd0ddd01cc7845d67eae281d52523a1
Patch-mainline: v5.6-rc1
References: jsc#SLE-12680, jsc#SLE-12880, jsc#SLE-12882, jsc#SLE-12883, jsc#SLE-13496, jsc#SLE-15322
Assume that the HW starts off with tag 0 "active" and so avoid using tag
0 for our own first ELSP submission.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191229183153.3719869-2-chris@chris-wilson.co.uk
Signed-off-by: Patrik Jakobsson <pjakobsson@suse.de>
---
drivers/gpu/drm/i915/gt/intel_lrc.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c
index 716bd7a01bab..711431522ee8 100644
--- a/drivers/gpu/drm/i915/gt/intel_lrc.c
+++ b/drivers/gpu/drm/i915/gt/intel_lrc.c
@@ -1108,7 +1108,7 @@ __execlists_schedule_in(struct i915_request *rq)
/* We don't need a strict matching tag, just different values */
ce->lrc_desc &= ~GENMASK_ULL(47, 37);
ce->lrc_desc |=
- (u64)(engine->context_tag++ % NUM_CONTEXT_TAG) <<
+ (u64)(++engine->context_tag % NUM_CONTEXT_TAG) <<
GEN11_SW_CTX_ID_SHIFT;
BUILD_BUG_ON(NUM_CONTEXT_TAG > GEN12_MAX_CONTEXT_HW_ID);
}
@@ -2933,6 +2933,8 @@ static void enable_execlists(struct intel_engine_cs *engine)
RING_HWS_PGA,
i915_ggtt_offset(engine->status_page.vma));
ENGINE_POSTING_READ(engine, RING_HWS_PGA);
+
+ engine->context_tag = 0;
}
static bool unexpected_starting_state(struct intel_engine_cs *engine)
--
2.28.0