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

Jani Nikula
2015-06-17T11:54:10Z

On Wed, 17 Jun 2015, Jani Nikula <jani.nikula@linux.intel.com> wrote:
> On Wed, 17 Jun 2015, Chris Wilson <chris@chris-wilson.co.uk> wrote:
>> On Wed, Jun 17, 2015 at 02:01:57PM +1000, Dave Airlie wrote:
>>> From: Dave Airlie <airlied@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@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@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