diff --git a/sound/firewire/amdtp.c b/sound/firewire/amdtp.c
index ea995af..4b08b25 100644
--- a/sound/firewire/amdtp.c
+++ b/sound/firewire/amdtp.c
@@ -268,7 +268,7 @@
 
 	channels = s->pcm_channels;
 	src = (void *)runtime->dma_area +
-			s->pcm_buffer_pointer * (runtime->frame_bits / 8);
+			frames_to_bytes(runtime, s->pcm_buffer_pointer);
 	remaining_frames = runtime->buffer_size - s->pcm_buffer_pointer;
 	frame_step = s->data_block_quadlets - channels;
 
@@ -294,7 +294,7 @@
 
 	channels = s->pcm_channels;
 	src = (void *)runtime->dma_area +
-			s->pcm_buffer_pointer * (runtime->frame_bits / 8);
+			frames_to_bytes(runtime, s->pcm_buffer_pointer);
 	remaining_frames = runtime->buffer_size - s->pcm_buffer_pointer;
 	frame_step = s->data_block_quadlets - channels;