diff --git a/drivers/media/video/cx18/cx18-audio.c b/drivers/media/video/cx18/cx18-audio.c
index 7a8ad59..3526892 100644
--- a/drivers/media/video/cx18/cx18-audio.c
+++ b/drivers/media/video/cx18/cx18-audio.c
@@ -26,14 +26,18 @@
 #include "cx18-cards.h"
 #include "cx18-audio.h"
 
-#define CX18_AUDIO_ENABLE 0xc72014
+#define CX18_AUDIO_ENABLE    0xc72014
+#define CX18_AI1_MUX_MASK    0x30
+#define CX18_AI1_MUX_I2S1    0x00
+#define CX18_AI1_MUX_I2S2    0x10
+#define CX18_AI1_MUX_843_I2S 0x20
 
 /* Selects the audio input and output according to the current
    settings. */
 int cx18_audio_set_io(struct cx18 *cx)
 {
 	const struct cx18_card_audio_input *in;
-	u32 val;
+	u32 u, v;
 	int err;
 
 	/* Determine which input to use */
@@ -52,9 +56,37 @@
 		return err;
 
 	/* FIXME - this internal mux should be abstracted to a subdev */
-	val = cx18_read_reg(cx, CX18_AUDIO_ENABLE) & ~0x30;
-	val |= (in->audio_input > CX18_AV_AUDIO_SERIAL2) ? 0x20 :
-					(in->audio_input << 4);
-	cx18_write_reg_expect(cx, val | 0xb00, CX18_AUDIO_ENABLE, val, 0x30);
+	u = cx18_read_reg(cx, CX18_AUDIO_ENABLE);
+	v = u & ~CX18_AI1_MUX_MASK;
+	switch (in->audio_input) {
+	case CX18_AV_AUDIO_SERIAL1:
+		v |= CX18_AI1_MUX_I2S1;
+		break;
+	case CX18_AV_AUDIO_SERIAL2:
+		v |= CX18_AI1_MUX_I2S2;
+		break;
+	default:
+		v |= CX18_AI1_MUX_843_I2S;
+		break;
+	}
+	if (v == u) {
+		/* force a toggle of some AI1 MUX control bits */
+		u &= ~CX18_AI1_MUX_MASK;
+		switch (in->audio_input) {
+		case CX18_AV_AUDIO_SERIAL1:
+			u |= CX18_AI1_MUX_843_I2S;
+			break;
+		case CX18_AV_AUDIO_SERIAL2:
+			u |= CX18_AI1_MUX_843_I2S;
+			break;
+		default:
+			u |= CX18_AI1_MUX_I2S1;
+			break;
+		}
+		cx18_write_reg_expect(cx, u | 0xb00, CX18_AUDIO_ENABLE,
+				      u, CX18_AI1_MUX_MASK);
+	}
+	cx18_write_reg_expect(cx, v | 0xb00, CX18_AUDIO_ENABLE,
+			      v, CX18_AI1_MUX_MASK);
 	return 0;
 }