diff --git a/drivers/gpu/drm/i915/intel_sprite.c b/drivers/gpu/drm/i915/intel_sprite.c
index d2e003d8f3db..5170a0f5fe7b 100644
--- a/drivers/gpu/drm/i915/intel_sprite.c
+++ b/drivers/gpu/drm/i915/intel_sprite.c
@@ -494,7 +494,7 @@ skl_program_plane(struct intel_plane *plane,
 
 	keymax = (key->max_value & 0xffffff) | PLANE_KEYMAX_ALPHA(alpha);
 
-	keymsk = key->channel_mask & 0x3ffffff;
+	keymsk = key->channel_mask & 0x7ffffff;
 	if (alpha < 0xff)
 		keymsk |= PLANE_KEYMSK_ALPHA_ENABLE;