[Intel-gfx] [RFC PATCH 4/5] drm: i915: add DisplayPort amp unmute for LPE audio mode

[Pierre-Louis Bossart]

>>>>> +#define AUD_PORT_EN_B_DBG		0x62F20
>>>>> +#define AUD_PORT_EN_C_DBG		0x62F28
>>>>> +#define AUD_PORT_EN_D_DBG		0x62F2C
>>> These match the spec. But to match the standard i915 convention they
>>> should be called _AUD_PORT_EN_B_DBG etc. Same forthe chicken bit
>>> register.
>> Actually they just match one version of the spec I had lying around.
>> Another versions says:
>>
>> AUD_PORT_EN_B_DBG 0x62F20
>> AUD_PORT_EN_C_DBG 0x62F30
>> AUD_PORT_EN_D_DBG 0x62F34
> That's it!  Now finally I can hear the audio from DP3 with the
> additional patch below.
Wow. Thanks Ville for looking into this, we could have lost a lot of 
time. Do you happen to know if those previous values are due to poor 
documentation or a different skew we'd need to support, e.g. with a 
PCI-Id quirk?
At any rate, 2 days to get DP audio working is pretty nice, this was a 
good week.