[Intel-gfx] [PATCH 2/4] i915: add support for GPU side of MST audio

[Jani Nikula]

On Wed, 17 Jun 2015, Jani Nikula <jani.nikula at linux.intel.com> wrote:
> On Wed, 17 Jun 2015, Chris Wilson <chris at chris-wilson.co.uk> wrote:
>> On Wed, Jun 17, 2015 at 02:01:57PM +1000, Dave Airlie wrote:
>>> From: Dave Airlie <airlied at redhat.com>
>>> 
>>> This just adds enables for the codecs and debugfs
>>> support for mst connectors to print the audio info.
>>> 
>>> This relies on patches to the audio code to do anything
>>> more useful.
>>> 
>>> Signed-off-by: Dave Airlie <airlied at redhat.com>
>>> ---
>>> @@ -231,6 +231,7 @@ static void hsw_audio_codec_enable(struct drm_connector *connector,
>>>  	/* Reset ELD write address */
>>>  	tmp = I915_READ(HSW_AUD_DIP_ELD_CTRL(pipe));
>>>  	tmp &= ~IBX_ELD_ADDRESS_MASK;
>>> +	tmp |= ((pipe + 1) << 29);
>>>  	I915_WRITE(HSW_AUD_DIP_ELD_CTRL(pipe), tmp);
>>
>> This is not MST specific. Is this a bug fix we want ASAP?
>
>
> """
> This read-only bit reflects which port is used to transmit the DIP
> data. This can only change when DIP is disabled. If one or more
> audio-related DIP packets is enabled and audio is enabled on a digital
> port, these bits will reflect the digital port to which audio is
> directed.
>
> For DP MST, this is the device select/pipe select.
> """
>
> We shouldn't mess with the field if it's regular DP. Also "pipe + 1" is
> too magic; unfortunately I don't know what it should be. :(

Also, should mask out anything that was there before!

BR,
Jani.

>
> BR,
> Jani.
>
>
>
>
>
>
>
>> -Chris
>>
>> -- 
>> Chris Wilson, Intel Open Source Technology Centre
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>> Intel-gfx at lists.freedesktop.org
>> http://lists.freedesktop.org/mailman/listinfo/intel-gfx
>
> -- 
> Jani Nikula, Intel Open Source Technology Center

-- 
Jani Nikula, Intel Open Source Technology Center