Re: [PATCH v3 1/4] ASoC: es8316: judge PCM rate at later timing
On 2019/09/05 0:30, Mark Brown wrote: On Thu, Sep 05, 2019 at 12:06:23AM +0900, Katsuhiro Suzuki wrote: Would you tell me one more thing. I don't understand who sets MCLK to 0. Is it needed original machine driver instead of audio-graph-card? On my test environment (audio-graph-card + Rockchip I2S + ES8316), it seems audio-graph-card has never called set_sysclk() with freq = 0 after stop play/capture sound. So my env will go to bad scenario as I described in this patch. You shouldn't need a custom machine driver - you'll just be the first person who ran into this with audio-graph-card. I'd just add this support to the audio-graph-card, either with custom startup and shutdown callbacks or using a set_bias_level() callback (both get used, I'd guess the set_bias_level() is easier since you don't need to reference count anything). Oh, I understand current situation. I'll try it. Thanks for your support! Best Regards, Katsuhiro Suzuki
Re: [PATCH v3 1/4] ASoC: es8316: judge PCM rate at later timing
On Thu, Sep 05, 2019 at 12:06:23AM +0900, Katsuhiro Suzuki wrote: > Would you tell me one more thing. I don't understand who sets MCLK to 0. > Is it needed original machine driver instead of audio-graph-card? > On my test environment (audio-graph-card + Rockchip I2S + ES8316), it > seems audio-graph-card has never called set_sysclk() with freq = 0 after > stop play/capture sound. So my env will go to bad scenario as I described in > this patch. You shouldn't need a custom machine driver - you'll just be the first person who ran into this with audio-graph-card. I'd just add this support to the audio-graph-card, either with custom startup and shutdown callbacks or using a set_bias_level() callback (both get used, I'd guess the set_bias_level() is easier since you don't need to reference count anything). signature.asc Description: PGP signature
Re: [PATCH v3 1/4] ASoC: es8316: judge PCM rate at later timing
Hello Mark, On 2019/09/04 2:48, Mark Brown wrote: On Wed, Sep 04, 2019 at 01:53:19AM +0900, Katsuhiro Suzuki wrote: Root cause of this strange behavior is changing constraints list at set_sysclk timing. It seems that is too early to determine. So this patch does not use constraints list and check PCM rate limit more later timing at hw_params. hw_params is a bit late to impose constraints, you want them to be available to be available to the application before it gets as far as picking the parameters it wants so that you don't get hw_params failing due to an invalid configuration. That makes everything run more smoothly, applications should be able to trust the constraints they got and some will not handle failures well. The way this works with the variable MCLKs is that you end up in one of two cases (wm8731 and wm8741 do this): 1. The system is idle, MCLK is set to 0. In this case no constraints are set and we just set MCLK to whatever is required in hw_params() in the machine driver. 2. One direction is active, MCLK is set to whatever that needed. In this case startup() sets constraints derived from the MCLK. There are races in this if streams are being started and torn down simultaneously, there's not much we can do about them with the API the way it is so we do have to validate in hw_params() anyway but it should be validation not constraint imposition. If the system has a fixed MCLK it just sets that on probe then we always get the constraints applied on startup through the same code that handles case 2. Thank you for explanation. I agree with apply no constraints if MCLK is set to 0, and suitable constraints if MCLK is set to other values like as wm8731 and wm8741 drivers. I'll change my patch set and send. Would you tell me one more thing. I don't understand who sets MCLK to 0. Is it needed original machine driver instead of audio-graph-card? On my test environment (audio-graph-card + Rockchip I2S + ES8316), it seems audio-graph-card has never called set_sysclk() with freq = 0 after stop play/capture sound. So my env will go to bad scenario as I described in this patch. Best Regards, Katsuhiro Suzuki
Re: [PATCH v3 1/4] ASoC: es8316: judge PCM rate at later timing
On Wed, Sep 04, 2019 at 01:53:19AM +0900, Katsuhiro Suzuki wrote: > Root cause of this strange behavior is changing constraints list at > set_sysclk timing. It seems that is too early to determine. So this > patch does not use constraints list and check PCM rate limit more > later timing at hw_params. hw_params is a bit late to impose constraints, you want them to be available to be available to the application before it gets as far as picking the parameters it wants so that you don't get hw_params failing due to an invalid configuration. That makes everything run more smoothly, applications should be able to trust the constraints they got and some will not handle failures well. The way this works with the variable MCLKs is that you end up in one of two cases (wm8731 and wm8741 do this): 1. The system is idle, MCLK is set to 0. In this case no constraints are set and we just set MCLK to whatever is required in hw_params() in the machine driver. 2. One direction is active, MCLK is set to whatever that needed. In this case startup() sets constraints derived from the MCLK. There are races in this if streams are being started and torn down simultaneously, there's not much we can do about them with the API the way it is so we do have to validate in hw_params() anyway but it should be validation not constraint imposition. If the system has a fixed MCLK it just sets that on probe then we always get the constraints applied on startup through the same code that handles case 2. signature.asc Description: PGP signature
