[alsa-devel] Declaring HDMI channel allocation to kernel
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
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.
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
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
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
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
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
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.
participants (6)
-
Gabriel Beddingfield -
Gabriel M. Beddingfield
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Mark Brown -
Pierre-Louis Bossart -
Ricardo Neri -
Takashi Iwai