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));
 }
 
 /**