V4L/DVB (3266): Fix NICAM buzz on analog sound
Marcin Rudowski [Mon, 6 Feb 2006 11:15:14 +0000 (09:15 -0200)]
Apparently, having the number of lines fixed at 4 reduces (or even kills)
the buzz found in NICAM stereo with analog sound.

Signed-off-by: Marcin Rudowski <mar_rud@poczta.onet.pl>
Signed-off-by: Ricardo Cerqueira <v4l@cerqueira.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

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

index 8d6d6a6..3720f24 100644 (file)
@@ -787,12 +787,14 @@ static int set_pll(struct cx88_core *core, int prescale, u32 ofreq)
 
 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;
        /* 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);
+       cx88_sram_channel_setup(core, &cx88_sram_channels[SRAM_CH25], bpl, 0);
+       cx88_sram_channel_setup(core, &cx88_sram_channels[SRAM_CH26], bpl, 0);
 
-       cx_write(MO_AUDD_LNGTH,    128); /* fifo bpl size */
-       cx_write(MO_AUDR_LNGTH,    128); /* fifo bpl size */
+       cx_write(MO_AUDD_LNGTH, bpl); /* fifo bpl size */
+       cx_write(MO_AUDR_LNGTH, bpl); /* fifo bpl size */
 
        /* start dma */
        cx_write(MO_AUD_DMACNTRL, 0x0003); /* Up and Down fifo enable */