1 files changed, 42 insertions, 3 deletions

diff --git a/drivers/gpu/drm/i915/intel_guc.c b/drivers/gpu/drm/i915/intel_guc.c
index 230aea69385d..8660af3fd755 100644
--- a/drivers/gpu/drm/i915/intel_guc.c
+++ b/drivers/gpu/drm/i915/intel_guc.c
@@ -50,7 +50,8 @@ void intel_guc_init_send_regs(struct intel_guc *guc)
 	unsigned int i;
 
 	guc->send_regs.base = i915_mmio_reg_offset(SOFT_SCRATCH(0));
-	guc->send_regs.count = SOFT_SCRATCH_COUNT - 1;
+	guc->send_regs.count = GUC_MAX_MMIO_MSG_LEN;
+	BUILD_BUG_ON(GUC_MAX_MMIO_MSG_LEN > SOFT_SCRATCH_COUNT);
 
 	for (i = 0; i < guc->send_regs.count; i++) {
 		fw_domains |= intel_uncore_forcewake_for_reg(dev_priv,
@@ -521,6 +522,44 @@ int intel_guc_auth_huc(struct intel_guc *guc, u32 rsa_offset)
 	return intel_guc_send(guc, action, ARRAY_SIZE(action));
 }
 
+/*
+ * The ENTER/EXIT_S_STATE actions queue the save/restore operation in GuC FW and
+ * then return, so waiting on the H2G is not enough to guarantee GuC is done.
+ * When all the processing is done, GuC writes INTEL_GUC_SLEEP_STATE_SUCCESS to
+ * scratch register 14, so we can poll on that. Note that GuC does not ensure
+ * that the value in the register is different from
+ * INTEL_GUC_SLEEP_STATE_SUCCESS while the action is in progress so we need to
+ * take care of that ourselves as well.
+ */
+static int guc_sleep_state_action(struct intel_guc *guc,
+				  const u32 *action, u32 len)
+{
+	struct drm_i915_private *dev_priv = guc_to_i915(guc);
+	int ret;
+	u32 status;
+
+	I915_WRITE(SOFT_SCRATCH(14), INTEL_GUC_SLEEP_STATE_INVALID_MASK);
+
+	ret = intel_guc_send(guc, action, len);
+	if (ret)
+		return ret;
+
+	ret = __intel_wait_for_register(dev_priv, SOFT_SCRATCH(14),
+					INTEL_GUC_SLEEP_STATE_INVALID_MASK,
+					0, 0, 10, &status);
+	if (ret)
+		return ret;
+
+	if (status != INTEL_GUC_SLEEP_STATE_SUCCESS) {
+		DRM_ERROR("GuC failed to change sleep state. "
+			  "action=0x%x, err=%u\n",
+			  action[0], status);
+		return -EIO;
+	}
+
+	return 0;
+}
+
 /**
  * intel_guc_suspend() - notify GuC entering suspend state
  * @guc:	the guc
@@ -533,7 +572,7 @@ int intel_guc_suspend(struct intel_guc *guc)
 		intel_guc_ggtt_offset(guc, guc->shared_data)
 	};
 
-	return intel_guc_send(guc, data, ARRAY_SIZE(data));
+	return guc_sleep_state_action(guc, data, ARRAY_SIZE(data));
 }
 
 /**
@@ -571,7 +610,7 @@ int intel_guc_resume(struct intel_guc *guc)
 		intel_guc_ggtt_offset(guc, guc->shared_data)
 	};
 
-	return intel_guc_send(guc, data, ARRAY_SIZE(data));
+	return guc_sleep_state_action(guc, data, ARRAY_SIZE(data));
 }
 
 /**