diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 6cc55c1..e5071af 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -8987,6 +8987,8 @@ enum {
 #define     GEN6_PCODE_UNIMPLEMENTED_CMD	0xFF
 #define     GEN7_PCODE_TIMEOUT			0x2
 #define     GEN7_PCODE_ILLEGAL_DATA		0x3
+#define     GEN11_PCODE_ILLEGAL_SUBCOMMAND	0x4
+#define     GEN11_PCODE_LOCKED			0x6
 #define     GEN7_PCODE_MIN_FREQ_TABLE_GT_RATIO_OUT_OF_RANGE 0x10
 #define   GEN6_PCODE_WRITE_RC6VIDS		0x4
 #define   GEN6_PCODE_READ_RC6VIDS		0x5
diff --git a/drivers/gpu/drm/i915/intel_sideband.c b/drivers/gpu/drm/i915/intel_sideband.c
index cbfb717..3361fdc 100644
--- a/drivers/gpu/drm/i915/intel_sideband.c
+++ b/drivers/gpu/drm/i915/intel_sideband.c
@@ -365,6 +365,10 @@ static inline int gen7_check_mailbox_status(u32 mbox)
 		return -ETIMEDOUT;
 	case GEN7_PCODE_ILLEGAL_DATA:
 		return -EINVAL;
+	case GEN11_PCODE_ILLEGAL_SUBCOMMAND:
+		return -ENXIO;
+	case GEN11_PCODE_LOCKED:
+		return -EBUSY;
 	case GEN7_PCODE_MIN_FREQ_TABLE_GT_RATIO_OUT_OF_RANGE:
 		return -EOVERFLOW;
 	default: