diff --git a/sys/dev/pci/drm/i915/display/intel_gmbus.c b/sys/dev/pci/drm/i915/display/intel_gmbus.c
index a772962a993..eccf63962e1 100644
--- a/sys/dev/pci/drm/i915/display/intel_gmbus.c
+++ b/sys/dev/pci/drm/i915/display/intel_gmbus.c
@@ -605,8 +605,10 @@ gmbus_xfer_read_chunk(struct intel_display *display,
 
 		val = intel_de_read_fw(display, GMBUS3(display));
 		do {
-			if (extra_byte_added && len == 1)
+			if (extra_byte_added && len == 1) {
+				len--;
 				break;
+			}
 
 			*buf++ = val & 0xff;
 			val >>= 8;