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

[Nirmoy Das]

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.

Signed-off-by: Nirmoy Das <nirmoy.das at intel.com>
---
 drivers/gpu/drm/i915/i915_driver.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_driver.c b/drivers/gpu/drm/i915/i915_driver.c
index b870c0df081a..2fecdb8f189a 100644
--- a/drivers/gpu/drm/i915/i915_driver.c
+++ b/drivers/gpu/drm/i915/i915_driver.c
@@ -827,6 +827,7 @@ 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;
 
@@ -867,6 +868,7 @@ 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);
@@ -1089,6 +1091,8 @@ 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
@@ -1276,6 +1280,7 @@ 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;
 }
-- 
2.39.0