From e7a8b765983adc64e86b3f0b61eb8ecd8ff21d11 Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Tue, 28 Jul 2020 16:21:09 +0100
Subject: [PATCH] drm/i915/gt: Disable preparser around xcs invalidations on
 tgl

Unlike rcs where we have conclusive evidence from our selftesting that
disabling the preparser before performing the TLB invalidate and
relocations does impact upon the GPU execution, the evidence for the
same requirement on xcs is much more circumstantial. Let's apply the
preparser disable between batches as we invalidate the TLB as a dose of
healthy paranoia, just in case.

References: https://gitlab.freedesktop.org/drm/intel/-/issues/2169
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200728152110.830-1-chris@chris-wilson.co.uk
---
 drivers/gpu/drm/i915/gt/intel_lrc.c | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c
index 29c0fde8b4df3..353b1717fe847 100644
--- a/drivers/gpu/drm/i915/gt/intel_lrc.c
+++ b/drivers/gpu/drm/i915/gt/intel_lrc.c
@@ -4764,14 +4764,21 @@ static int gen12_emit_flush(struct i915_request *request, u32 mode)
 	intel_engine_mask_t aux_inv = 0;
 	u32 cmd, *cs;
 
+	cmd = 4;
+	if (mode & EMIT_INVALIDATE)
+		cmd += 2;
 	if (mode & EMIT_INVALIDATE)
 		aux_inv = request->engine->mask & ~BIT(BCS0);
+	if (aux_inv)
+		cmd += 2 * hweight8(aux_inv) + 2;
 
-	cs = intel_ring_begin(request,
-			      4 + (aux_inv ? 2 * hweight8(aux_inv) + 2 : 0));
+	cs = intel_ring_begin(request, cmd);
 	if (IS_ERR(cs))
 		return PTR_ERR(cs);
 
+	if (mode & EMIT_INVALIDATE)
+		*cs++ = preparser_disable(true);
+
 	cmd = MI_FLUSH_DW + 1;
 
 	/* We always require a command barrier so that subsequent
@@ -4804,6 +4811,10 @@ static int gen12_emit_flush(struct i915_request *request, u32 mode)
 		}
 		*cs++ = MI_NOOP;
 	}
+
+	if (mode & EMIT_INVALIDATE)
+		*cs++ = preparser_disable(false);
+
 	intel_ring_advance(request, cs);
 
 	return 0;
-- 
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