diff --git a/drivers/gpu/drm/i915/gt/intel_gt_mcr.c b/drivers/gpu/drm/i915/gt/intel_gt_mcr.c
index 0b414eae1683..2c0f1f3e28ff 100644
--- a/drivers/gpu/drm/i915/gt/intel_gt_mcr.c
+++ b/drivers/gpu/drm/i915/gt/intel_gt_mcr.c
@@ -376,9 +376,26 @@ void intel_gt_mcr_lock(struct intel_gt *gt, unsigned long *flags)
 	 * driver threads, but also with hardware/firmware agents.  A dedicated
 	 * locking register is used.
 	 */
-	if (GRAPHICS_VER_FULL(gt->i915) >= IP_VER(12, 70))
+	if (GRAPHICS_VER_FULL(gt->i915) >= IP_VER(12, 70)) {
+		/*
+		 * The steering control and semaphore registers are inside an
+		 * "always on" power domain with respect to RC6.  However there
+		 * are some issues if higher-level platform sleep states are
+		 * entering/exiting at the same time these registers are
+		 * accessed.  Grabbing GT forcewake and holding it over the
+		 * entire lock/steer/unlock cycle ensures that those sleep
+		 * states have been fully exited before we access these
+		 * registers.  This wakeref will be released in the unlock
+		 * routine.
+		 *
+		 * This is expected to become a formally documented/numbered
+		 * workaround soon.
+		 */
+		intel_uncore_forcewake_get(gt->uncore, FORCEWAKE_GT);
+
 		err = wait_for(intel_uncore_read_fw(gt->uncore,
 						    MTL_STEER_SEMAPHORE) == 0x1, 100);
+	}
 
 	/*
 	 * Even on platforms with a hardware lock, we'll continue to grab
@@ -415,8 +432,11 @@ void intel_gt_mcr_unlock(struct intel_gt *gt, unsigned long flags)
 {
 	spin_unlock_irqrestore(&gt->mcr_lock, flags);
 
-	if (GRAPHICS_VER_FULL(gt->i915) >= IP_VER(12, 70))
+	if (GRAPHICS_VER_FULL(gt->i915) >= IP_VER(12, 70)) {
 		intel_uncore_write_fw(gt->uncore, MTL_STEER_SEMAPHORE, 0x1);
+
+		intel_uncore_forcewake_put(gt->uncore, FORCEWAKE_GT);
+	}
 }
 
 /**