[PATCH 3/3] drm/i915: Enable GGTT blitting in MTL

[Oak Zeng]

From: Nirmoy Das <nirmoy.das at intel.com>

MTL can hang because of a HW bug while parallel reading/writing
from/to LMEM/GTTMMADR BAR so try to reduce GGTT update
related pci transactions with blitter command as recommended
for Wa_22018444074.

To issue blitter commands, the driver must be primed to receive
requests. Maintain blitter-based GGTT update disablement until driver
probing completes. Moreover, implement a temporary disablement
of blitter prior to entering suspend, followed by re-enablement
post-resume. This is acceptable as those transition periods are
mostly single threaded.

v2: Disable GGTT blitter prior to runtime suspend and re-enable
after runtime resume.

Signed-off-by: Nirmoy Das <nirmoy.das at intel.com>
Signed-off-by: Oak Zeng <oak.zeng at intel.com>
---
 drivers/gpu/drm/i915/i915_driver.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_driver.c b/drivers/gpu/drm/i915/i915_driver.c
index 0ad0c5885ec2..217cb199c28e 100644
--- a/drivers/gpu/drm/i915/i915_driver.c
+++ b/drivers/gpu/drm/i915/i915_driver.c
@@ -825,6 +825,7 @@ int i915_driver_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 	i915_welcome_messages(i915);
 
 	i915->do_release = true;
+	intel_engine_blitter_context_set_ready(to_gt(i915), true);
 
 	return 0;
 
@@ -865,6 +866,7 @@ void i915_driver_remove(struct drm_i915_private *i915)
 {
 	intel_wakeref_t wakeref;
 
+	intel_engine_blitter_context_set_ready(to_gt(i915), false);
 	wakeref = intel_runtime_pm_get(&i915->runtime_pm);
 
 	i915_driver_unregister(i915);
@@ -1087,6 +1089,8 @@ static int i915_drm_suspend(struct drm_device *dev)
 	struct pci_dev *pdev = to_pci_dev(dev_priv->drm.dev);
 	pci_power_t opregion_target_state;
 
+	intel_engine_blitter_context_set_ready(to_gt(dev_priv), false);
+
 	disable_rpm_wakeref_asserts(&dev_priv->runtime_pm);
 
 	/* We do a lot of poking in a lot of registers, make sure they work
@@ -1274,6 +1278,7 @@ static int i915_drm_resume(struct drm_device *dev)
 	intel_gvt_resume(dev_priv);
 
 	enable_rpm_wakeref_asserts(&dev_priv->runtime_pm);
+	intel_engine_blitter_context_set_ready(to_gt(dev_priv), true);
 
 	return 0;
 }
@@ -1523,6 +1528,7 @@ static int intel_runtime_suspend(struct device *kdev)
 	if (drm_WARN_ON_ONCE(&dev_priv->drm, !HAS_RUNTIME_PM(dev_priv)))
 		return -ENODEV;
 
+	intel_engine_blitter_context_set_ready(to_gt(dev_priv), false);
 	drm_dbg(&dev_priv->drm, "Suspending device\n");
 
 	disable_rpm_wakeref_asserts(rpm);
@@ -1661,6 +1667,8 @@ static int intel_runtime_resume(struct device *kdev)
 	else
 		drm_dbg(&dev_priv->drm, "Device resumed\n");
 
+	intel_engine_blitter_context_set_ready(to_gt(dev_priv), true);
+
 	return ret;
 }
 
-- 
2.26.3