[alsa-devel] HCTL element callback

[Jaroslav Kysela]

On Fri, 3 Sep 2010, Camilo Polymeris wrote:

> On Fri, 2010-09-03 at 09:16 +0200, Jaroslav Kysela wrote:
>> On Fri, 3 Sep 2010, Camilo Polymeris wrote:
>>
>>> On Fri, 2010-09-03 at 08:35 +0200, Jaroslav Kysela wrote:
>>>> On Thu, 2 Sep 2010, Camilo Polymeris wrote:
>>>>
>>>>> Hello.
>>>>> I am writing this mixer app:
>>>>> http://emutrix.googlecode.com
>>>>>
>>>>> I have trouble with callbacks. So far I have implemented callbacks for
>>>>> the master volume fader and clock rate selection (integer and enum,
>>>>> resp.)
>>>>> But "pad" callbacks (boolean) won't work. In fact, I have noticed that
>>>>> alsamixer 1.0.22 also doesn't react to pad changes from the application.
>>>>> But the driver reacts to both as expected, so we're dealing with the
>>>>> same element.
>>>>
>>>> It seems like a bug in the emu driver. The elem put callbacks does not
>>>> check for changes (they should return 1).
>>>>
>>>> Does this patch help?
>>>>
>>>> diff --git a/sound/pci/emu10k1/emumixer.c b/sound/pci/emu10k1/emumixer.c
>>>> index 05afe06..7bd1c1a 100644
>>>> --- a/sound/pci/emu10k1/emumixer.c
>>>> +++ b/sound/pci/emu10k1/emumixer.c
>>>> @@ -622,6 +622,7 @@ static int snd_emu1010_adc_pads_put(struct snd_kcontrol *kcontrol, struct snd_ct
>>>>   	if (cache != emu->emu1010.adc_pads) {
>>>>   		snd_emu1010_fpga_write(emu, EMU_HANA_ADC_PADS, cache );
>>>>   	        emu->emu1010.adc_pads = cache;
>>>> +	        return 1;
>>>>   	}
>>>>
>>>>   	return 0;
>>>> @@ -670,6 +671,7 @@ static int snd_emu1010_dac_pads_put(struct snd_kcontrol *kcontrol, struct snd_ct
>>>>   	if (cache != emu->emu1010.dac_pads) {
>>>>   		snd_emu1010_fpga_write(emu, EMU_HANA_DAC_PADS, cache );
>>>>   	        emu->emu1010.dac_pads = cache;
>>>> +	        return 1;
>>>>   	}
>>>>
>>>>   	return 0;
>>>>
>>>>  					Jaroslav
>>>>
>>>> -----
>>>> Jaroslav Kysela <perex at perex.cz>
>>>> Linux Kernel Sound Maintainer
>>>> ALSA Project, Red Hat, Inc.
>>>>
>>>
>>>
>>> Hello.
>>> I think it doesn't help. I applied the patch, built the sources,
>>> installed them (with 'make install') and reloaded alsa (with 'alsa
>>> reload'). That should have installed the new module, right?
>>> If so, the patch didn't help. I am not very experienced with kernel
>>> stuff, so if I did something wrong, please tell me and I'll try again.
>>
>> Reboot your machine at first to ensure that you have loaded new ALSA
>> kernel modules.
>>
>>  					Jaroslav
>>
>
> Very nice. That worked. Thanks!
> By the way, I have noticed two small errors (I think) with element
> names:
> * Pads are labeled 14dB, but they are actually ~12dB (intended as
> -10dBV/+4dBu)
> * Enum items (inputs) are labeled 0202 SPDIF Left/Right, but the
> connector is on the 1010 card. The outputs are ok.
> Are you keeping those for backwards-compatibility?

The whole emu card support code is from James. So these questions should 
go to him.

 						Jaroslav

-----
Jaroslav Kysela <perex at perex.cz>
Linux Kernel Sound Maintainer
ALSA Project, Red Hat, Inc.