[alsa-devel] Question about WM8904 regcache
Hi Mark, I am sorry to disturb you. On our EK board, it use wm8904 codec. When I enable the audio, and use alsa utils aplay to test, I meet the following issue. The audio can not playback, it show the following error. ---8>--- #aplay 44.1k_16bit_stereo.wav Playing WAVE '44.1k_16bit_stereo.wav' : Signed 16 bit Little Endian, Rate 44100 Hz, Stereo aplay: pcm_write:1737: write error: Input/output error ---<8---
After check the register, they are not be configured correctly. When read from debug file system, found the cache_dirty always Y before playback and also failed playback. I try to add the following two line in wm8904_set_bias_level into "case SND_SOC_BIAS_ON", it doesn't work. ---8>--- @@ -1832,9 +1834,12 @@ static int wm8904_set_bias_level(struct snd_soc_codec *codec,
switch (level) { case SND_SOC_BIAS_ON: + regcache_cache_only(wm8904->regmap, false); + regcache_sync(wm8904->regmap); break; ---<8---
However, If I comment the regcache_cache_only(wm8904->regmap, true) as following, then it play OK. ---8>--- @@ -2232,7 +2239,7 @@ static int wm8904_i2c_probe(struct i2c_client *i2c, WM8904_POBCTRL, 0);
/* Can leave the device powered off until we need it */ - regcache_cache_only(wm8904->regmap, true); + // regcache_cache_only(wm8904->regmap, true); ---<8---
So, any clue for this issue?
Thanks.
Best Regards, Bo Shen
On Fri, Jul 12, 2013 at 03:00:26PM +0800, Bo Shen wrote:
I try to add the following two line in wm8904_set_bias_level into "case SND_SOC_BIAS_ON", it doesn't work. ---8>--- @@ -1832,9 +1834,12 @@ static int wm8904_set_bias_level(struct snd_soc_codec *codec,
switch (level) { case SND_SOC_BIAS_ON:
regcache_cache_only(wm8904->regmap, false);regcache_sync(wm8904->regmap); break;---<8---
That's far too late to be doing that, the device is already supposed to be powered and running - you can see the device is doing this already in the transition from _OFF to _STANDBY which is where it should happen.
However, If I comment the regcache_cache_only(wm8904->regmap, true) as following, then it play OK. ---8>--- @@ -2232,7 +2239,7 @@ static int wm8904_i2c_probe(struct i2c_client *i2c, WM8904_POBCTRL, 0);
/* Can leave the device powered off until we need it */
regcache_cache_only(wm8904->regmap, true);
// regcache_cache_only(wm8904->regmap, true);---<8---
So, any clue for this issue?
The device is supposed to be idle_bias_off so sitting in _BIAS_OFF when not in use, this should mean a transition to _STANDBY as part of the power up sequence which should reenable interaction with the device. Check to see why that is not happening - _OFF should be the default bias level as well.
Hi Mark,
On 07/12/2013 04:42 PM, Mark Brown wrote:
On Fri, Jul 12, 2013 at 03:00:26PM +0800, Bo Shen wrote:
I try to add the following two line in wm8904_set_bias_level into "case SND_SOC_BIAS_ON", it doesn't work. ---8>--- @@ -1832,9 +1834,12 @@ static int wm8904_set_bias_level(struct snd_soc_codec *codec,
switch (level) { case SND_SOC_BIAS_ON:
regcache_cache_only(wm8904->regmap, false);regcache_sync(wm8904->regmap); break;---<8---
That's far too late to be doing that, the device is already supposed to be powered and running - you can see the device is doing this already in the transition from _OFF to _STANDBY which is where it should happen.
However, If I comment the regcache_cache_only(wm8904->regmap, true) as following, then it play OK. ---8>--- @@ -2232,7 +2239,7 @@ static int wm8904_i2c_probe(struct i2c_client *i2c, WM8904_POBCTRL, 0);
/* Can leave the device powered off until we need it */
regcache_cache_only(wm8904->regmap, true);
// regcache_cache_only(wm8904->regmap, true);---<8---
So, any clue for this issue?
The device is supposed to be idle_bias_off so sitting in _BIAS_OFF when not in use, this should mean a transition to _STANDBY as part of the power up sequence which should reenable interaction with the device. Check to see why that is not happening - _OFF should be the default bias level as well.
Do you mean the system boot up the device should be in _BIAS_OFF state?
I add debug info to set_bias_level function, and don't see this is called when system boot up. When I run aplay command, it call from _STANDBY to _ON, not _OFF, after show the error message, it call from _PREPARE to _OFF.
---8>--- # aplay 44.1k_16bit_stereo.wav Playing WAVE '44.1k_16bit_stereo.wav' : Signed 16 bit Little Endian, Rate 44100 Hz, Stereo
leve is: 1 leve is: 2 leve is: 3
aplay: pcm_write:1737: write error: Input/output error # >>>>>> leve is: 2
leve is: 1 leve is: 0
---<8---
Best Regards, Bo Shen
On Fri, Jul 12, 2013 at 06:03:16PM +0800, Bo Shen wrote:
Do you mean the system boot up the device should be in _BIAS_OFF state?
Yes.
I add debug info to set_bias_level function, and don't see this is called when system boot up. When I run aplay command, it call from _STANDBY to _ON, not _OFF, after show the error message, it call from _PREPARE to _OFF.
It's not called on boot, it's just the default state - the probe() function is intended to leave things in _OFF. What you describe sounds like it's sitting in _STANDBY, you need to debug why this is happening. I can't see anything in current code - snd_soc_register_codec() sets the bias level to _OFF by default.
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Mark Brown