[PATCH] drm/i915: Exprimental resume speedup.

[Thomas Hellström]

Signed-off-by: Thomas Hellström <thomas.hellstrom at linux.intel.com>
---
 drivers/gpu/drm/i915/gt/intel_ggtt.c | 24 +++++++++++++++++++++++-
 drivers/gpu/drm/i915/gt/intel_gtt.h  |  3 +++
 drivers/gpu/drm/i915/i915_driver.c   |  5 +++++
 3 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/gt/intel_ggtt.c b/drivers/gpu/drm/i915/gt/intel_ggtt.c
index 04191fe2ee34..d74cb871c348 100644
--- a/drivers/gpu/drm/i915/gt/intel_ggtt.c
+++ b/drivers/gpu/drm/i915/gt/intel_ggtt.c
@@ -1180,6 +1180,8 @@ static int i915_gmch_probe(struct i915_ggtt *ggtt)
 		ggtt->do_idle_maps = true;
 	}
 
+	ggtt->restored = true;
+
 	ggtt->vm.insert_page = i915_ggtt_insert_page;
 	ggtt->vm.insert_entries = i915_ggtt_insert_entries;
 	ggtt->vm.clear_range = i915_ggtt_clear_range;
@@ -1309,11 +1311,26 @@ bool i915_ggtt_resume_vm(struct i915_address_space *vm)
 {
 	struct i915_vma *vma;
 	bool write_domain_objs = false;
+	bool retained_ptes;
 
 	drm_WARN_ON(&vm->i915->drm, !vm->is_ggtt && !vm->is_dpt);
 
 	/* First fill our portion of the GTT with scratch pages */
-	vm->clear_range(vm, 0, vm->total);
+	retained_ptes =
+		/* Only matters where writing PTEs is slow */
+		GRAPHICS_VER(vm->i915) >= 8 &&
+                /* LMEM never retains content on suspend */
+		!HAS_LMEM(vm->i915) &&
+		/*
+		 * If this is a GGTT vm and we restored from hibernate,
+		 * content is lost.
+		 */
+		(vm->is_ggtt && !i915_vm_to_ggtt(vm)->restored);
+
+	if (!retained_ptes) {
+		pr_err("Retained ptes was: %d\n", (int)retained_ptes);
+		vm->clear_range(vm, 0, vm->total);
+	}
 
 	/* clflush objects bound into the GGTT and rebind them. */
 	list_for_each_entry(vma, &vm->bound_list, vm_link) {
@@ -1352,3 +1369,8 @@ void i915_ggtt_resume(struct i915_ggtt *ggtt)
 
 	intel_ggtt_restore_fences(ggtt);
 }
+
+void i915_ggtt_mark_restored(struct drm_i915_private *i915, bool val)
+{
+	to_gt(i915)->ggtt->restored = val;
+}
diff --git a/drivers/gpu/drm/i915/gt/intel_gtt.h b/drivers/gpu/drm/i915/gt/intel_gtt.h
index 4529b5e9f6e6..d16b3aa7ecc7 100644
--- a/drivers/gpu/drm/i915/gt/intel_gtt.h
+++ b/drivers/gpu/drm/i915/gt/intel_gtt.h
@@ -345,6 +345,8 @@ struct i915_ggtt {
 
 	bool do_idle_maps;
 
+	bool restored;
+
 	int mtrr;
 
 	/** Bit 6 swizzling required for X tiling */
@@ -570,6 +572,7 @@ void i915_ggtt_suspend_vm(struct i915_address_space *vm);
 bool i915_ggtt_resume_vm(struct i915_address_space *vm);
 void i915_ggtt_suspend(struct i915_ggtt *gtt);
 void i915_ggtt_resume(struct i915_ggtt *ggtt);
+void i915_ggtt_mark_restored(struct drm_i915_private *i915, bool val);
 
 void
 fill_page_dma(struct drm_i915_gem_object *p, const u64 val, unsigned int count);
diff --git a/drivers/gpu/drm/i915/i915_driver.c b/drivers/gpu/drm/i915/i915_driver.c
index 64e6f76861f9..d77a28d4980f 100644
--- a/drivers/gpu/drm/i915/i915_driver.c
+++ b/drivers/gpu/drm/i915/i915_driver.c
@@ -1425,6 +1425,8 @@ static int i915_pm_suspend(struct device *kdev)
 		return -ENODEV;
 	}
 
+	i915_ggtt_mark_restored(i915, false);
+
 	if (i915->drm.switch_power_state == DRM_SWITCH_POWER_OFF)
 		return 0;
 
@@ -1536,6 +1538,9 @@ static int i915_pm_restore_early(struct device *kdev)
 
 static int i915_pm_restore(struct device *kdev)
 {
+	struct drm_i915_private *i915 = kdev_to_i915(kdev);
+
+	i915_ggtt_mark_restored(i915, true);
 	return i915_pm_resume(kdev);
 }
 
-- 
2.34.1