Re: [alsa-devel] Multiple codecs on one sound card for multi-channel sound card
Hi guys,
Where are we now with TDM on several codecs on the same TDM channel ? I'm sorry to dig out this old thread but I couldn't really find any proper information about that.
I only plan to use 4 channel TDM with two codecs. I'm using IMX6's SSI as master for both codec.
What I've got working today is 1 codec with ssi as I2S master.
Do you have any pointer on what is achieved so far and how to implement it ?
I'm using kernel *v4.14.78*.
Any pointer to DTS achieving that or audio card doing that kind of thing would already be an amazing first hint.!
Regards,
Yann
Got it. Thanks Arnaud.
-Caleb
On Thu, Sep 17, 2015 at 9:09 AM, arnaud.mouiche at invoxia.com http://mailman.alsa-project.org/mailman/listinfo/alsa-devel <arnaud.mouiche at invoxia.com http://mailman.alsa-project.org/mailman/listinfo/alsa-devel> wrote:
*> Le 17/09/2015 17:34, Caleb Crome a écrit :
*>>>>>>* On Thu, Sep 17, 2015 at 7:33 AM, arnaud.mouiche at invoxia.com http://mailman.alsa-project.org/mailman/listinfo/alsa-devel *>>>* <arnaud.mouiche at invoxia.com http://mailman.alsa-project.org/mailman/listinfo/alsa-devel> wrote: *>>>>>>>>* hello, *>>>>>>>*> Le 17/09/2015 15:38, Caleb Crome a écrit : *>>>>>>>>>>* On Thu, Sep 17, 2015 at 1:51 AM, arnaud.mouiche at invoxia.com http://mailman.alsa-project.org/mailman/listinfo/alsa-devel *>>>>>* <arnaud.mouiche at invoxia.com http://mailman.alsa-project.org/mailman/listinfo/alsa-devel> wrote: *>>>>>>>>>>>>* Hello Caleb, *>>>>>>>>>>>>* freescale SSI is fine with more than 2 channels. *>>>>>>* I have planed to publish a set of patch in this direction but we still *>>>>>>* have *>>>>>>* some corner cases to fix first (rare issues with channels alignment) *>>>>>>>>>>* I'd love to see anything you're willing to show :-) *>>>>>>>>>>>* Yet, this following is far enough to have it working. *>>>>>>* And since the max/min rate is at the end the intersection of what the *>>>>>>* SSI, *>>>>>>* the codec and the card are declaring, it will not change anything until *>>>>>>* you *>>>>>>* connect the SSI to a codec with more than 2 channels, or a multi-codec *>>>>>>* solution. *>>>>*> *>>>>* What if I change channels_max to 16 for capture and playback? Last *>>>>>* time I tried, it would not keep the channels synchronized on the TDM *>>>>>* bus. I tried playing with the FIFO settings, which helped, but it *>>>>>* still would not start each channel in the right slot reliably. *>>>>>* Perhaps I was using an older kernel. *>>>>>>>>* you put the finger on what's hurting ! ;) *>>>>>>>>* In fact, we made 8 channels working in reliable way on imx50, with *>>>>* predictive latency ... with an old kernel (3.17) ... based on freescale *>>>>* BSP... on sound/soc/imx/imx-ssi.c (something that doesn't exist outside *>>>>* freescale BSP) *>>>>>>>>* Well, just to say it is doable on any recent imx since the hardware is *>>>>* not *>>>>* the issue. But the job was a set of awful hacks. *>>>>>>* Sorry, I don't quite understand. Are you saying that on a recent *>>>* kernel (say 4.1 or 4.2), you think it will just work. Or are yo *>>>* saying that even on a modern kernel it's a set of awful hacks? And *>>>* should I use fsl_ssi.c or imx-ssi.c (device tree/non device tree) *>>>* version? *>>>>* - I'm saying it is working on recent upstream kernel, using *>>* sound/soc/fsl/fsl_ssi.c, but with *>>* some channel sync issues in rare conditions (at least 4 channels case, *>>* opening multiple SSI at the same time). *>>* So, you should test on your side with you setup, and simply be prepared to *>>* not see it working as a charm. *>>>>* - we made it work perfectly, but on an old freescale BSP, where freescale *>>* rewrites a SSI driver different from the already 2 drivers (device tree/non *>>* device tree) available today in upstream + lot of awful hacks => so, this is *>>* not a hardware issue. *>>>>* - when I will have time, I will start from the upstream driver, and make it *>>* work correctly with 8 channels (or more) *>>>>* arnaud *>>>>>>>>* In short, what's your best current recommendation to get it working today? *>>>>>>>* My plan was to re-do all this job on an upstream kernel, in a way it can *>>>>* be *>>>>* accepted. *>>>>* Unfortunately you will have to wait, I'm under pressure for other stuff *>>>>* right now. *>>>>>>* Heh, understood. If there's anything I can do to help, let me know. *>>>>>>* Thanks, *>>>* -Caleb *>>>>>>>* Regards, *>>>>* arnaud *>>>>>>>>>>>>>* I'll give it a try again. Like I said, we'd love to get our *>>>>>* 16-channel board up and running on the MX6, so I'm definitely *>>>>>* motivated to put some work in to get it reliable. *>>>>>>>>>>* Thanks, *>>>>>* -Caleb *>>>>>>>
Hello Yann,
Everything should now be a question of DTS.
Here you will find a post from Caleb with a DTS which set a TDM configuration on imx6 https://medium.com/@caleb_22836/how-to-get-the-mx6-ssi-port-up-and-running-i...
Yet, It was for test purpose only and use a dummy codec (snd-soc-dummy) as single multi slots pseudo codec. At least it gives you some entries to set the SSI in TDM mode...
For the multi-codec part, I don't have working example tested right now, but - sound/soc/soc-core.c::snd_soc_of_get_dai_link_codecs() is used when parsing the device tree to build the list of codecs. You can use it as a starting point to review how everything is working. - few Documentation device tree example are using the multi-codec notation. yet, samsung,odroid.txt is one. you will find:
codec { sound-dai = <&hdmi>, <&max98090>; };
My advise: - make it working in TDM with one codec. - once working fine, enable mode codecs in DTS simply by adding the second codec in "sound-dai" list. Then check how ALSA controls/widgets are made available for useland (ie. run "amixer ccontents")
Please, don't forget to provide you working DTS and experience in this mailing list for reference.
Regards, Arnaud
On 12/02/2019 11:55, Yann CARDAILLAC wrote:
Hi guys,
Where are we now with TDM on several codecs on the same TDM channel ? I'm sorry to dig out this old thread but I couldn't really find any proper information about that.
I only plan to use 4 channel TDM with two codecs. I'm using IMX6's SSI as master for both codec.
What I've got working today is 1 codec with ssi as I2S master.
Do you have any pointer on what is achieved so far and how to implement it ?
I'm using kernel *v4.14.78*.
Any pointer to DTS achieving that or audio card doing that kind of thing would already be an amazing first hint.!
Regards,
Yann
Got it. Thanks Arnaud. -Caleb
On Thu, Sep 17, 2015 at 9:09 AM, arnaud.mouiche at invoxia.com http://mailman.alsa-project.org/mailman/listinfo/alsa-devel <arnaud.mouiche at invoxia.com http://mailman.alsa-project.org/mailman/listinfo/alsa-devel> wrote:
*> Le 17/09/2015 17:34, Caleb Crome a écrit :
*>>>>>>* On Thu, Sep 17, 2015 at 7:33 AM, arnaud.mouiche at invoxia.com http://mailman.alsa-project.org/mailman/listinfo/alsa-devel *>>>* <arnaud.mouiche at invoxia.com http://mailman.alsa-project.org/mailman/listinfo/alsa-devel> wrote: *>>>>>>>>* hello, *>>>>>>>*> Le 17/09/2015 15:38, Caleb Crome a écrit : *>>>>>>>>>>* On Thu, Sep 17, 2015 at 1:51 AM, arnaud.mouiche at invoxia.com http://mailman.alsa-project.org/mailman/listinfo/alsa-devel *>>>>>* <arnaud.mouiche at invoxia.com http://mailman.alsa-project.org/mailman/listinfo/alsa-devel> wrote: *>>>>>>>>>>>>* Hello Caleb, *>>>>>>>>>>>>* freescale SSI is fine with more than 2 channels. *>>>>>>* I have planed to publish a set of patch in this direction but we still *>>>>>>* have *>>>>>>* some corner cases to fix first (rare issues with channels alignment) *>>>>>>>>>>* I'd love to see anything you're willing to show :-) *>>>>>>>>>>>* Yet, this following is far enough to have it working. *>>>>>>* And since the max/min rate is at the end the intersection of what the *>>>>>>* SSI, *>>>>>>* the codec and the card are declaring, it will not change anything until *>>>>>>* you *>>>>>>* connect the SSI to a codec with more than 2 channels, or a multi-codec *>>>>>>* solution. *>>>>*> *>>>>* What if I change channels_max to 16 for capture and playback? Last *>>>>>* time I tried, it would not keep the channels synchronized on the TDM *>>>>>* bus. I tried playing with the FIFO settings, which helped, but it *>>>>>* still would not start each channel in the right slot reliably. *>>>>>* Perhaps I was using an older kernel. *>>>>>>>>* you put the finger on what's hurting ! ;) *>>>>>>>>* In fact, we made 8 channels working in reliable way on imx50, with *>>>>* predictive latency ... with an old kernel (3.17) ... based on freescale *>>>>* BSP... on sound/soc/imx/imx-ssi.c (something that doesn't exist outside *>>>>* freescale BSP) *>>>>>>>>* Well, just to say it is doable on any recent imx since the hardware is *>>>>* not *>>>>* the issue. But the job was a set of awful hacks. *>>>>>>* Sorry, I don't quite understand. Are you saying that on a recent *>>>* kernel (say 4.1 or 4.2), you think it will just work. Or are yo *>>>* saying that even on a modern kernel it's a set of awful hacks? And *>>>* should I use fsl_ssi.c or imx-ssi.c (device tree/non device tree) *>>>* version? *>>>>* - I'm saying it is working on recent upstream kernel, using *>>* sound/soc/fsl/fsl_ssi.c, but with *>>* some channel sync issues in rare conditions (at least 4 channels case, *>>* opening multiple SSI at the same time). *>>* So, you should test on your side with you setup, and simply be prepared to *>>* not see it working as a charm. *>>>>* - we made it work perfectly, but on an old freescale BSP, where freescale *>>* rewrites a SSI driver different from the already 2 drivers (device tree/non *>>* device tree) available today in upstream + lot of awful hacks => so, this is *>>* not a hardware issue. *>>>>* - when I will have time, I will start from the upstream driver, and make it *>>* work correctly with 8 channels (or more) *>>>>* arnaud *>>>>>>>>* In short, what's your best current recommendation to get it working today? *>>>>>>>* My plan was to re-do all this job on an upstream kernel, in a way it can *>>>>* be *>>>>* accepted. *>>>>* Unfortunately you will have to wait, I'm under pressure for other stuff *>>>>* right now. *>>>>>>* Heh, understood. If there's anything I can do to help, let me know. *>>>>>>* Thanks, *>>>* -Caleb *>>>>>>>* Regards, *>>>>* arnaud *>>>>>>>>>>>>>* I'll give it a try again. Like I said, we'd love to get our *>>>>>* 16-channel board up and running on the MX6, so I'm definitely *>>>>>* motivated to put some work in to get it reliable. *>>>>>>>>>>* Thanks, *>>>>>* -Caleb *>>>>>>>
participants (2)
-
Arnaud Mouiche -
Yann CARDAILLAC