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Commit 17801f5f authored by Marcin Rudowski's avatar Marcin Rudowski Committed by Mauro Carvalho Chehab
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V4L/DVB (3266): Fix NICAM buzz on analog sound 



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: default avatarMarcin Rudowski <mar_rud@poczta.onet.pl>
Signed-off-by: default avatarRicardo Cerqueira <v4l@cerqueira.org>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@infradead.org>
parent bbab6fd8

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

+6 −4
Original line number Diff line number Diff line
@@ -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 */