Hi Morimoto-san
Thanks for your comments
On 2018/10/04 12:43, Kuninori Morimoto wrote:
Hi Jiada
Thank you for your feedback
in GEN3 SSI may use different BUSIF for data transfer, this patch adds busif property to each dai stream, to indicate the BUSIF used by playback/capture stream.
Also adds rsnd_ssi_select_busif() to automatically select BUSIF (currently only BUSIF0 is selected)
Signed-off-by: Jiada Wang jiada_wang@mentor.com
(snip)
And this patch selects it on runtime (= hw_param) ?
Because, in order to automatically determine BUSIF number, information like SSI mode (non-Split/Split/Ex-Split), runtime channel, are required (in our internal implementation, SSI mode is selected by kctrl) because of this, in this patch, BUSIF is selected on runtime
But, I think we can/should select it on probe timing from DT connection. Am I misunderstanding ?
with the above reasoning, BUSIF is selected on runtime. what do you think?
I have no objection that you are customizing your kernel locally. But, upstreaming kernel based on it is not acceptable for me. I'm not sure detail of your local implementation, but I don't think we need to select SSI mode by kctrl. If my understanding was correct, it can also be selected automatically somehow. Or, am I misunderstanding ?
SSI can work in following modes 1. Basic Mode: (channel 1, 2, 4, 6, 8, 16) 2. TDM Extended Mode: (channel 6, 8) 3. TDM Split Mode: (channel 1, 2) 4. TDM Ex-Split mode: (Channel 2, 4, 6, 8, 10)
for example user asks dai-link0 to playback 2ch audio stream, driver can't determine which mode to work, as it can be Basic mode, Split mode or Ex-Split mode.
I could understand what you want to do, and yes, I can agree that we want/need to have it on upstream. Thank you very much to indicating it to me. But we need to consider more how to implement it. Especially, it is related to DT bindings. As you already know, if it is implemented on upstream kernel, we need to keep compatibility in the future, and it is very difficult.
Yes, I agree with you, upstream need to consider lots of things
So, my opinions for BUSIFn support are
- SSI mode should be selected automatically
can you give me your idea, how to automatically determine working mode, when user plays 2 channel stream on playback dai-link
- BUSIFn connection should be selected on DT
since which BUSIFx is used during audio data transfer, is not consideration of user, I think your previous suggestion, (automatically select BUSIFx) makes more sense
Thanks, Jiada
(I think we don't want random sound output position ?) - To select it, we need to have new "ssiu" DT seetings, or parse sound card. Maybe adding ssiu is realistic.Best regards
Kuninori Morimoto