Enable audio DMA restart on channel change even when cx88-alsa is compiled

From: Ricardo Cerqueira <v4l@cerqueira.org>

cx88-alsa can be compiled in (in distro built kernels, for example), but
not used. In those cases, the audio DMA restart is needed for proper sound
on NICAM channels.
This patch enables the DMA restart even with ALSA, but the functions now
check if cx88-alsa is really active.

Signed-off-by: Ricardo Cerqueira <v4l@cerqueira.org>

1 files changed, 10 insertions, 0 deletions

diff --git a/linux/drivers/media/video/cx88/cx88-core.c b/linux/drivers/media/video/cx88/cx88-core.c
index fbbb6ecf5..849e5bef1 100644
--- a/linux/drivers/media/video/cx88/cx88-core.c
+++ b/linux/drivers/media/video/cx88/cx88-core.c
@@ -832,6 +832,11 @@ int cx88_start_audio_dma(struct cx88_core *core)
 {
 	/* constant 128 made buzz in analog Nicam-stereo for bigger fifo_size */
 	int bpl = cx88_sram_channels[SRAM_CH25].fifo_size/4;
+
+	/* If downstream RISC is enabled, bail out; ALSA is managing DMA */
+	if (cx_read(MO_AUD_DMACNTRL) & 0x10)
+		return 0;
+
 	/* setup fifo + format */
 	cx88_sram_channel_setup(core, &cx88_sram_channels[SRAM_CH25], bpl, 0);
 	cx88_sram_channel_setup(core, &cx88_sram_channels[SRAM_CH26], bpl, 0);
@@ -841,11 +846,16 @@ int cx88_start_audio_dma(struct cx88_core *core)
 
 	/* start dma */
 	cx_write(MO_AUD_DMACNTRL, 0x0003); /* Up and Down fifo enable */
+
 	return 0;
 }
 
 int cx88_stop_audio_dma(struct cx88_core *core)
 {
+	/* If downstream RISC is enabled, bail out; ALSA is managing DMA */
+	if (cx_read(MO_AUD_DMACNTRL) & 0x10)
+		return 0;
+
 	/* stop dma */
 	cx_write(MO_AUD_DMACNTRL, 0x0000);