[alsa-devel] Lost dB volumes on USB headset between 2.6.38 and 3.0

[Colin Guthrie]

'Twas brillig, and Takashi Iwai at 09/08/11 13:40 did gyre and gimble:
> At Tue, 09 Aug 2011 13:19:37 +0200,
> Colin Guthrie wrote:
>>
>> 'Twas brillig, and Clemens Ladisch at 09/08/11 12:39 did gyre and gimble:
>>> David Henningsson wrote:
>>>> Hmm, I and Colin Guthrie have found a regression between kernels 2.6.38
>>>> and 3.0.
>>>>
>>>> When running "amixer -D hw:handset" for this device under 2.6.38, the
>>>> attached file is returned. Under 3.0, the dB information is missing.
>>>> This can't be intentional, can it?
>>>
>>> There are patches that might have introduced bugs, but these two patches
>>> do remove dB information intentionally:
>>>
>>> ALSA: usb-audio - Don't expose broken dB ranges:
>>> http://git.alsa-project.org/?p=alsa-kernel.git;a=commitdiff;h=59bb7f0eebe6
>>> ALSA: usb-audio - Add volume range check and warn if it too big:
>>> http://git.alsa-project.org/?p=alsa-kernel.git;a=commitdiff;h=80acefff3bc7
>>>
>>> Are there any messages in the system log when loading the driver?
>>> What are the controls' dB ranges (see "amixer contents")?
>>
>> Interesting thanks fpr the hints.
>>
>> I get this when plugging in the device David mentioned previously.
>>
>>
>> usb 3-1: USB disconnect, device number 2
>> usbcore: deregistering interface driver snd-usb-audio
>> usb 2-1: new full speed USB device number 7 using uhci_hcd
>> usb 2-1: New USB device found, idVendor=1885, idProduct=0501
>> usb 2-1: New USB device strings: Mfr=2, Product=1, SerialNumber=0
>> usb 2-1: Product: BT Agile handset
>> usb 2-1: Manufacturer: Ascalade
>> input: Ascalade BT Agile handset as
>> /devices/pci0000:00/0000:00:1d.1/usb2/2-1/2-1:1.3/input/input14
>> generic-usb 0003:1885:0501.0006: input,hidraw0: USB HID v1.00 Device
>> [Ascalade BT Agile handset] on usb-0000:00:1d.1-1/input3
>> 13:0: cannot get min/max values for control 2 (id 13)
>> 14:0: cannot get min/max values for control 2 (id 14)
>> 9:0: cannot get min/max values for control 2 (id 9)
>> 10:0: cannot get min/max values for control 2 (id 10)
>> 11:0: cannot get min/max values for control 2 (id 11)
>> 9:0: cannot get min/max values for control 2 (id 9)
>> 14:0: cannot get min/max values for control 2 (id 14)
>> 11:0: cannot get min/max values for control 2 (id 11)
>> 13:0: cannot get min/max values for control 2 (id 13)
>> 10:0: cannot get min/max values for control 2 (id 10)
>> 9:0: cannot get min/max values for control 2 (id 9)
> 
> So the problem is that the driver can't extract the dB values.
> If the problem is seen only at the beginning of driver initialization,
> the patch below may work.
> 
> Also, could you give "lsusb -v" output, too?

Sure here it is. I actually have two USB cards plugged in here, both of
which have now lost their dB info. The one above is here and the new one
is the Yamaha one.


> diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c
> index c04d7c7..cdd19d7 100644
> --- a/sound/usb/mixer.c
> +++ b/sound/usb/mixer.c
> @@ -152,6 +152,7 @@ static inline void check_mapped_dB(const struct usbmix_name_map *p,
>  	if (p && p->dB) {
>  		cval->dBmin = p->dB->min;
>  		cval->dBmax = p->dB->max;
> +		cval->initialized = 1;
>  	}
>  }
>  
> @@ -1092,7 +1093,7 @@ static void build_feature_ctl(struct mixer_build *state, void *raw_desc,
>  				" Switch" : " Volume");
>  		if (control == UAC_FU_VOLUME) {
>  			check_mapped_dB(map, cval);
> -			if (cval->dBmin < cval->dBmax) {
> +			if (cval->dBmin < cval->dBmax || !cval->initialized) {
>  				kctl->tlv.c = mixer_vol_tlv;
>  				kctl->vd[0].access |= 
>  					SNDRV_CTL_ELEM_ACCESS_TLV_READ |



Not had a chance to test this yet but I will when I get a moment.

Col


-- 

Colin Guthrie
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http://colin.guthr.ie/

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