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

[Oak Zeng]

From: Nirmoy Das <nirmoy....@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. (Oak)

Signed-off-by: Nirmoy Das <nirmoy....@intel.com>
Signed-off-by: Oak Zeng <oak.z...@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 f8dbee7a5af7..6afe0adc8ddb 100644
--- a/drivers/gpu/drm/i915/i915_driver.c
+++ b/drivers/gpu/drm/i915/i915_driver.c
@@ -815,6 +815,7 @@ 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;
 
@@ -855,6 +856,7 @@ 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);
@@ -1077,6 +1079,8 @@ 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
@@ -1264,6 +1268,7 @@ 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;
 }
@@ -1515,6 +1520,7 @@ 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);
@@ -1669,6 +1675,8 @@ 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