diff options
| -rw-r--r-- | drivers/media/video/cx88/cx88-tvaudio.c | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/drivers/media/video/cx88/cx88-tvaudio.c b/drivers/media/video/cx88/cx88-tvaudio.c index 99e120483ec..9aee8c51ee2 100644 --- a/drivers/media/video/cx88/cx88-tvaudio.c +++ b/drivers/media/video/cx88/cx88-tvaudio.c @@ -62,6 +62,10 @@ static unsigned int always_analog = 0; module_param(always_analog,int,0644); MODULE_PARM_DESC(always_analog,"force analog audio out"); +static unsigned int radio_deemphasis = 0; +module_param(radio_deemphasis,int,0644); +MODULE_PARM_DESC(radio_deemphasis, "Radio deemphasis time constant, " + "0=None, 1=50us (elsewhere), 2=75us (USA)"); #define dprintk(fmt, arg...) if (audio_debug) \ printk(KERN_DEBUG "%s/0: " fmt, core->name , ## arg) @@ -678,6 +682,10 @@ static void set_audio_standard_FM(struct cx88_core *core, }; /* It is enough to leave default values? */ + /* No, it's not! The deemphasis registers are reset to the 75us + * values by default. Analyzing the spectrum of the decoded audio + * reveals that "no deemphasis" is the same as 75 us, while the 50 us + * setting results in less deemphasis. */ static const struct rlist fm_no_deemph[] = { {AUD_POLYPH80SCALEFAC, 0x0003}, @@ -688,6 +696,7 @@ static void set_audio_standard_FM(struct cx88_core *core, set_audio_start(core, SEL_FMRADIO); switch (deemph) { + default: case FM_NO_DEEMPH: set_audio_registers(core, fm_no_deemph); break; @@ -757,7 +766,7 @@ void cx88_set_tvaudio(struct cx88_core *core) set_audio_standard_EIAJ(core); break; case WW_FM: - set_audio_standard_FM(core, FM_NO_DEEMPH); + set_audio_standard_FM(core, radio_deemphasis); break; case WW_NONE: default: |