Index: linux-2.6.21/sound/soc/pxa/pxa2xx-pcm.c
===================================================================
--- linux-2.6.21.orig/sound/soc/pxa/pxa2xx-pcm.c	2007-09-02 22:30:56.000000000 -0300
+++ linux-2.6.21/sound/soc/pxa/pxa2xx-pcm.c	2007-09-02 22:36:26.000000000 -0300
@@ -153,7 +153,8 @@
 static int pxa2xx_pcm_prepare(struct snd_pcm_substream *substream)
 {
 	struct pxa2xx_runtime_data *prtd = substream->runtime->private_data;
-
+	/* no dma if on loopback */
+	if (!prtd->params) return 0;
 	DCSR(prtd->dma_ch) &= ~DCSR_RUN;
 	DCSR(prtd->dma_ch) = 0;
 	DCMD(prtd->dma_ch) = 0;