Declaring HDMI channel allocation to kernel

Declaring HDMI channel allocation to kernel

[Gabriel M. Beddingfield]

Is there an established way for me (from userspace) to pass the HDMI 
Channel Allocation (1 byte) to the driver?  If not, can you recommend an 
approach?

In most of the drivers that I've inspected, the drivers seem to assume 
that there's a 1:1 mapping of Number-of-Channels to Channel-Allocation. 
  However, the HDMI sink declares which speakers it has attached in the 
EDID.  If I can match this in userspace... I need a way to communicate 
it to the driver.

-gabriel

Re: Declaring HDMI channel allocation to kernel

[Pierre-Louis Bossart]

On 7/23/2012 9:18 AM, Gabriel M. Beddingfield wrote:
>
> Is there an established way for me (from userspace) to pass the HDMI 
> Channel Allocation (1 byte) to the driver?  If not, can you recommend 
> an approach?
>
> In most of the drivers that I've inspected, the drivers seem to assume 
> that there's a 1:1 mapping of Number-of-Channels to 
> Channel-Allocation.  However, the HDMI sink declares which speakers it 
> has attached in the EDID.  If I can match this in userspace... I need 
> a way to communicate it to the driver.
I believe this is one of the topics that will be presented by Takashi at 
LPC, we need the ability to specify a arbitrary sink-specific channel 
mapping.

Re: Declaring HDMI channel allocation to kernel

[Gabriel M. Beddingfield]

On 07/23/2012 02:39 PM, Pierre-Louis Bossart wrote:
> On 7/23/2012 9:18 AM, Gabriel M. Beddingfield wrote:
>>
>> Is there an established way for me (from userspace) to pass the HDMI
>> Channel Allocation (1 byte) to the driver?  If not, can you recommend
>> an approach?
[snip[
> I believe this is one of the topics that will be presented by Takashi at
> LPC, we need the ability to specify a arbitrary sink-specific channel
> mapping.

OK, thanks!  So then, to do this today I need to add my own special sauce.

-gabriel

Re: Declaring HDMI channel allocation to kernel

[Takashi Iwai]

At Mon, 23 Jul 2012 14:39:38 -0500,
Pierre-Louis Bossart wrote:
> 
> On 7/23/2012 9:18 AM, Gabriel M. Beddingfield wrote:
> >
> > Is there an established way for me (from userspace) to pass the HDMI 
> > Channel Allocation (1 byte) to the driver?  If not, can you recommend 
> > an approach?
> >
> > In most of the drivers that I've inspected, the drivers seem to assume 
> > that there's a 1:1 mapping of Number-of-Channels to 
> > Channel-Allocation.  However, the HDMI sink declares which speakers it 
> > has attached in the EDID.  If I can match this in userspace... I need 
> > a way to communicate it to the driver.
> I believe this is one of the topics that will be presented by Takashi at 
> LPC, we need the ability to specify a arbitrary sink-specific channel 
> mapping.

Ah, sorry, this topic was canceled due to the time slot limitation.
But I can bring up the topic if we get another time slot, at BoF or
whatever.


Takashi

Re: Declaring HDMI channel allocation to kernel

[Mark Brown]

On Tue, Jul 24, 2012 at 02:33:13PM +0200, Takashi Iwai wrote:

> > I believe this is one of the topics that will be presented by Takashi at 
> > LPC, we need the ability to specify a arbitrary sink-specific channel 
> > mapping.

> Ah, sorry, this topic was canceled due to the time slot limitation.
> But I can bring up the topic if we get another time slot, at BoF or
> whatever.

I'd not expect it to take *too* long so we should be able to fit it in I
think.  I've not yet had time to work out all this new scheduling stuff
though.

Re: Declaring HDMI channel allocation to kernel

[Ricardo Neri]

Hi Gabriel,

On 07/24/2012 07:30 AM, Gabriel M. Beddingfield wrote:
> On 07/23/2012 02:39 PM, Pierre-Louis Bossart wrote:
>> On 7/23/2012 9:18 AM, Gabriel M. Beddingfield wrote:
>>>
>>> Is there an established way for me (from userspace) to pass the HDMI
>>> Channel Allocation (1 byte) to the driver?  If not, can you recommend
>>> an approach?
> [snip[
>> I believe this is one of the topics that will be presented by Takashi at
>> LPC, we need the ability to specify a arbitrary sink-specific channel
>> mapping.
>
> OK, thanks!  So then, to do this today I need to add my own special sauce.

FWIW, in the past I could use the route plugin to achieve arbitrary 
channel mapping. This was done by SW, though. The details are here:

http://mailman.alsa-project.org/pipermail/alsa-devel/2012-April/051573.html

Ricardo
>
> -gabriel
>
> _______________________________________________
> Alsa-devel mailing list
> Alsa-devel@alsa-project.org
> http://mailman.alsa-project.org/mailman/listinfo/alsa-devel

Re: Declaring HDMI channel allocation to kernel

[Gabriel Beddingfield]

Thanks, Ricardo.

Is this just re-arranging the chanels in-place?  I'm not sure that's
what I need.  In this case, I'm needing to be able to differentiate
between "quad" (FL, FR, RL, RR) and "surround" (FL, FR, FC, RC) in
order to support both.

-gabriel

On Tue, Jul 24, 2012 at 12:43 PM, Ricardo Neri <ricardo.neri@ti.com> wrote:
> Hi Gabriel,
>
>
> On 07/24/2012 07:30 AM, Gabriel M. Beddingfield wrote:
>>
>> On 07/23/2012 02:39 PM, Pierre-Louis Bossart wrote:
>>>
>>> On 7/23/2012 9:18 AM, Gabriel M. Beddingfield wrote:
>>>>
>>>>
>>>> Is there an established way for me (from userspace) to pass the HDMI
>>>> Channel Allocation (1 byte) to the driver?  If not, can you recommend
>>>> an approach?
>>
>> [snip[
>>>
>>> I believe this is one of the topics that will be presented by Takashi at
>>> LPC, we need the ability to specify a arbitrary sink-specific channel
>>> mapping.
>>
>>
>> OK, thanks!  So then, to do this today I need to add my own special sauce.
>
>
> FWIW, in the past I could use the route plugin to achieve arbitrary channel
> mapping. This was done by SW, though. The details are here:
>
> http://mailman.alsa-project.org/pipermail/alsa-devel/2012-April/051573.html
>
> Ricardo
>>
>>
>> -gabriel
>>
>>
>> _______________________________________________
>> Alsa-devel mailing list
>> Alsa-devel@alsa-project.org
>> http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
>
>

Re: Declaring HDMI channel allocation to kernel

[Ricardo Neri]

Hi Gabriel,
On 07/24/2012 01:55 PM, Gabriel Beddingfield wrote:
> Thanks, Ricardo.
>
> Is this just re-arranging the chanels in-place?  I'm not sure that's
> what I need.  In this case, I'm needing to be able to differentiate
> between "quad" (FL, FR, RL, RR) and "surround" (FL, FR, FC, RC) in
> order to support both.

Perhaps you could create two different devices, one for surround and 
another for quad, each having its own static reroute table. You would 
use the appropriate device for each specific use case.

Ricardo
>
> -gabriel
>
> On Tue, Jul 24, 2012 at 12:43 PM, Ricardo Neri <ricardo.neri@ti.com> wrote:
>> Hi Gabriel,
>>
>>
>> On 07/24/2012 07:30 AM, Gabriel M. Beddingfield wrote:
>>>
>>> On 07/23/2012 02:39 PM, Pierre-Louis Bossart wrote:
>>>>
>>>> On 7/23/2012 9:18 AM, Gabriel M. Beddingfield wrote:
>>>>>
>>>>>
>>>>> Is there an established way for me (from userspace) to pass the HDMI
>>>>> Channel Allocation (1 byte) to the driver?  If not, can you recommend
>>>>> an approach?
>>>
>>> [snip[
>>>>
>>>> I believe this is one of the topics that will be presented by Takashi at
>>>> LPC, we need the ability to specify a arbitrary sink-specific channel
>>>> mapping.
>>>
>>>
>>> OK, thanks!  So then, to do this today I need to add my own special sauce.
>>
>>
>> FWIW, in the past I could use the route plugin to achieve arbitrary channel
>> mapping. This was done by SW, though. The details are here:
>>
>> http://mailman.alsa-project.org/pipermail/alsa-devel/2012-April/051573.html
>>
>> Ricardo
>>>
>>>
>>> -gabriel
>>>
>>>
>>> _______________________________________________
>>> Alsa-devel mailing list
>>> Alsa-devel@alsa-project.org
>>> http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
>>
>>