[PATCH] V4L: Enables audio DMA setting on cx88 chips, even when dma not in use

- Enabled audio DMA transfer code even when DMA not in use to solve a
  problem on some broken cx88 chips.
Signed-off-by: Mauro Carvalho Chehab <mchehab@brturbo.com.br>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

drivers/media/video/cx88/cx88-core.c

@@ -837,6 +837,29 @@ static int set_pll(struct cx88_core *core, int prescale, u32 ofreq)
 	return -1;
 }
 
+int cx88_start_audio_dma(struct cx88_core *core)
+{
+	/* setup fifo + format */
+	cx88_sram_channel_setup(core, &cx88_sram_channels[SRAM_CH25], 128, 0);
+	cx88_sram_channel_setup(core, &cx88_sram_channels[SRAM_CH26], 128, 0);
+
+	cx_write(MO_AUDD_LNGTH,    128); /* fifo bpl size */
+	cx_write(MO_AUDR_LNGTH,    128); /* fifo bpl size */
+
+	/* start dma */
+	cx_write(MO_AUD_DMACNTRL, 0x0003); /* Up and Down fifo enable */
+
+	return 0;
+}
+
+int cx88_stop_audio_dma(struct cx88_core *core)
+{
+	/* stop dma */
+	cx_write(MO_AUD_DMACNTRL, 0x0000);
+
+	return 0;
+}
+
 static int set_tvaudio(struct cx88_core *core)
 {
 	struct cx88_tvnorm *norm = core->tvnorm;
@@ -877,9 +900,16 @@ static int set_tvaudio(struct cx88_core *core)
 	cx88_set_tvaudio(core);
 	/* cx88_set_stereo(dev,V4L2_TUNER_MODE_STEREO); */
 
+/*
+   This should be needed only on cx88-alsa. It seems that some cx88 chips have
+   bugs and does require DMA enabled for it to work.
+ */
+	cx88_start_audio_dma(core);
 	return 0;
 }
 
+
+
 int cx88_set_tvnorm(struct cx88_core *core, struct cx88_tvnorm *norm)
 {
 	u32 fsc8;
@@ -1201,6 +1231,8 @@ EXPORT_SYMBOL(cx88_set_scale);
 EXPORT_SYMBOL(cx88_vdev_init);
 EXPORT_SYMBOL(cx88_core_get);
 EXPORT_SYMBOL(cx88_core_put);
+EXPORT_SYMBOL(cx88_start_audio_dma);
+EXPORT_SYMBOL(cx88_stop_audio_dma);
 
 /*
  * Local variables:

drivers/media/video/cx88/cx88-tvaudio.c

@@ -132,7 +132,10 @@ static void set_audio_finish(struct cx88_core *core, u32 ctl)
 {
 	u32 volume;
 
+	/* restart dma; This avoids buzz in NICAM and is good in others  */
+	cx88_stop_audio_dma(core);
 	cx_write(AUD_RATE_THRES_DMD, 0x000000C0);
+	cx88_start_audio_dma(core);
 
 	if (cx88_boards[core->board].blackbird) {
 		/* sets sound input from external adc */

drivers/media/video/cx88/cx88.h

@@ -491,6 +491,10 @@ extern struct cx88_core* cx88_core_get(struct pci_dev *pci);
 extern void cx88_core_put(struct cx88_core *core,
 			  struct pci_dev *pci);
 
+extern int cx88_start_audio_dma(struct cx88_core *core);
+extern int cx88_stop_audio_dma(struct cx88_core *core);
+
+
 /* ----------------------------------------------------------- */
 /* cx88-vbi.c                                                  */