提交 17801f5f 编写于 作者: M Marcin Rudowski 提交者: Mauro Carvalho Chehab

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: NMarcin Rudowski <mar_rud@poczta.onet.pl>
Signed-off-by: NRicardo Cerqueira <v4l@cerqueira.org>
Signed-off-by: NMauro Carvalho Chehab <mchehab@infradead.org>
上级 bbab6fd8
......@@ -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 */
......
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