drm/i915: Take a runtime pm wakeref for atomic commits

Before we start prepping the system for an atomic modeset, wake the
device up. We then keep track of this wakeref until we complete the
atomic commit, so we hold keep the device awake for all potential HW
access, and do not allow the device to sleep with a pending modeset.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=110771Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190528075354.22341-1-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/intel_display.c

@@ -13834,6 +13834,7 @@ static void intel_atomic_commit_tail(struct drm_atomic_state *state)
 		intel_uncore_arm_unclaimed_mmio_detection(&dev_priv->uncore);
 		intel_display_power_put(dev_priv, POWER_DOMAIN_MODESET, wakeref);
 	}
+	intel_runtime_pm_put(dev_priv, intel_state->wakeref);
 
 	/*
 	 * Defer the cleanup of the old state to a separate worker to not
@@ -13912,6 +13913,8 @@ static int intel_atomic_commit(struct drm_device *dev,
 	struct drm_i915_private *dev_priv = to_i915(dev);
 	int ret = 0;
 
+	intel_state->wakeref = intel_runtime_pm_get(dev_priv);
+
 	drm_atomic_state_get(state);
 	i915_sw_fence_init(&intel_state->commit_ready,
 			   intel_atomic_commit_ready);
@@ -13948,6 +13951,7 @@ static int intel_atomic_commit(struct drm_device *dev,
 	if (ret) {
 		DRM_DEBUG_ATOMIC("Preparing state failed with %i\n", ret);
 		i915_sw_fence_commit(&intel_state->commit_ready);
+		intel_runtime_pm_put(dev_priv, intel_state->wakeref);
 		return ret;
 	}
 
@@ -13959,6 +13963,7 @@ static int intel_atomic_commit(struct drm_device *dev,
 		i915_sw_fence_commit(&intel_state->commit_ready);
 
 		drm_atomic_helper_cleanup_planes(dev, state);
+		intel_runtime_pm_put(dev_priv, intel_state->wakeref);
 		return ret;
 	}
 	dev_priv->wm.distrust_bios_wm = false;

drivers/gpu/drm/i915/intel_drv.h

@@ -420,6 +420,8 @@ struct dpll {
 struct intel_atomic_state {
 	struct drm_atomic_state base;
 
+	intel_wakeref_t wakeref;
+
 	struct {
 		/*
 		 * Logical state of cdclk (used for all scaling, watermark,