diff --git a/repos/os/include/audio_out_session/audio_out_session.h b/repos/os/include/audio_out_session/audio_out_session.h
index cc75cd1f6f..18d651ad4d 100644
--- a/repos/os/include/audio_out_session/audio_out_session.h
+++ b/repos/os/include/audio_out_session/audio_out_session.h
@@ -89,7 +89,7 @@ class Audio_out::Packet
 		 * \param  data  frames to copy in
 		 * \param  size  number of frames to copy
 		 */
-		void content(float *data, Genode::size_t samples)
+		void content(float const *data, Genode::size_t samples)
 		{
 			Genode::memcpy(_data, data, (samples > PERIOD ? PERIOD : samples) * SAMPLE_SIZE);