[wdmaudiodev] Re: UAC1 driver sends volume:0000
- From: Børge Strand-Bergesen <borge.strand@xxxxxxxxx>
- To: wdmaudiodev@xxxxxxxxxxxxx
- Date: Sat, 19 Mar 2016 13:48:51 +0100
Thanks Clemens!
On Sat, Mar 19, 2016 at 1:33 PM, Clemens Ladisch <clemens@xxxxxxxxxx> wrote:
Børge Strand-Bergesen wrote:
bDeviceClass 239 Miscellaneous Device
bDeviceSubClass 2 ?
bDeviceProtocol 1 Interface Association
...
Interface Association:
Interface association descriptors are used only in UAC version 2 (which
I'm sure Microsoft will add support for real soon, in a few decades or
so). For an UAC 1 device, just use device class 0.
We all agree on the politics here! The same device has both UAC1 and
UAC2 support. So I guess there is some cross-polination. The same code
used to have both ADC and DAC support. Now it's only DAC. I'll see how
much I'm able to figure out from your explanation.
Interface Descriptor:
bInterfaceNumber 0
bInterfaceClass 0 (Defined at Interface level)
This does not make sense. Why do you have this interface at all? Just
remove it, or mark it as vendor specific.
Dunno! The unit has audio OUT, feedback IN, HID and a control
interface for setting up some device parameters. I'm not a descriptor
expert, so I'll have to dig around and understand the implications of
this.
What I see in the Device firmware debug terminal is get_min value of
0x8000
This would be valid only for GET_CUR.
Pardon? I see all of get_min, get_max, get_cur_volume and get_cur_mute
calls when the device is plugged in. I see iOS doing both get_min and
get_cur when it wants to do a set_cur on the volume. Windows only does
set_cur.
get_max of 0x7FFF
Is this an audio device or a weapon?
Cannon of 1812 overture goes nuclear :-) Yes, it may be ripe for some
adjustment. I guess someone just put in the limits of the protocol and
never really planned to implement an OS controlled volume setting.
What are the actual volume capabilities of your hardware?
Up to 0dB :-) 2Vrms or so.
Cheers,
Børge
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