From 4c39654b4b834753fbd7f513c7f150abc2246508 Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Thu, 30 Jan 2020 09:22:38 +0000
Subject: drm/i915/gt: Skip global serialisation of clear_range for bxt vtd
Git-commit: bf72c8c6ee77d46f74a2b143303a9c9923f9e7a7
Patch-mainline: v5.7-rc1
References: jsc#SLE-12680, jsc#SLE-12880, jsc#SLE-12882, jsc#SLE-12883, jsc#SLE-13496, jsc#SLE-15322

VT'd on Broxton and on Braswell require serialisation of GGTT updates.
However, it seems to only be required for insertion, so drop the
complication and heavyweight stop_machine() for clears. The range will
be serialised again before use.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200130092239.1743672-1-chris@chris-wilson.co.uk
Signed-off-by: Patrik Jakobsson <pjakobsson@suse.de>
---
 drivers/gpu/drm/i915/gt/intel_ggtt.c | 27 ---------------------------
 1 file changed, 27 deletions(-)

diff --git a/drivers/gpu/drm/i915/gt/intel_ggtt.c b/drivers/gpu/drm/i915/gt/intel_ggtt.c
index 1fa3eb4401be..3c2a909012d8 100644
--- a/drivers/gpu/drm/i915/gt/intel_ggtt.c
+++ b/drivers/gpu/drm/i915/gt/intel_ggtt.c
@@ -350,31 +350,6 @@ static void bxt_vtd_ggtt_insert_entries__BKL(struct i915_address_space *vm,
 	stop_machine(bxt_vtd_ggtt_insert_entries__cb, &arg, NULL);
 }
 
-struct clear_range {
-	struct i915_address_space *vm;
-	u64 start;
-	u64 length;
-};
-
-static int bxt_vtd_ggtt_clear_range__cb(void *_arg)
-{
-	struct clear_range *arg = _arg;
-
-	gen8_ggtt_clear_range(arg->vm, arg->start, arg->length);
-	bxt_vtd_ggtt_wa(arg->vm);
-
-	return 0;
-}
-
-static void bxt_vtd_ggtt_clear_range__BKL(struct i915_address_space *vm,
-					  u64 start,
-					  u64 length)
-{
-	struct clear_range arg = { vm, start, length };
-
-	stop_machine(bxt_vtd_ggtt_clear_range__cb, &arg, NULL);
-}
-
 static void gen6_ggtt_clear_range(struct i915_address_space *vm,
 				  u64 start, u64 length)
 {
@@ -881,8 +856,6 @@ static int gen8_gmch_probe(struct i915_ggtt *ggtt)
 	    IS_CHERRYVIEW(i915) /* fails with concurrent use/update */) {
 		ggtt->vm.insert_entries = bxt_vtd_ggtt_insert_entries__BKL;
 		ggtt->vm.insert_page    = bxt_vtd_ggtt_insert_page__BKL;
-		if (ggtt->vm.clear_range != nop_clear_range)
-			ggtt->vm.clear_range = bxt_vtd_ggtt_clear_range__BKL;
 	}
 
 	ggtt->invalidate = gen8_ggtt_invalidate;
-- 
2.28.0