Re: sound over USB

[Greg KH <greg@kroah.com>]

On Tue, May 12, 2020 at 10:13:10PM +0530, Subhashini Rao Beerisetty wrote:
>  Hi all,
> 
> In my Linux machine, I connected the plantronics usb headset with mic
> and I see(with the help of dmesg) that this device detected.
> 
> 
> 
> [116676.507868] usb 2-2: new full-speed USB device number 5 using xhci_hcd
> [116676.923445] usb 2-2: New USB device found, idVendor=047f, idProduct=c012
>  [116676.927091] usb 2-2: New USB device strings: Mfr=1, Product=2,
> SerialNumber=0
>  [116676.934252] usb 2-2: Product: Plantronics .Audio 628 USB
>  [116676.941445] usb 2-2: Manufacturer: Plantronics
>  [116676.945731] usb 2-2: ep 0x84 - rounding interval to 64
> microframes, ep desc says 80 microframes
>  [116677.078071] hidraw: raw HID events driver (C) Jiri Kosina
>  [116677.159669] usbcore: registered new interface driver usbhid
>  [116677.161686] usbhid: USB HID core driver
>  [116677.175458] input: Plantronics Plantronics .Audio 628 USB as
> /devices/pci0000:00/0000:00:14.0/usb2/2-2/2-2:1.3/0003:047F:C012.0001/input/input4
>  [116677.234588] plantronics 0003:047F:C012.0001:
> input,hiddev0,hidraw0: USB HID v1.00 Device [Plantronics Plantronics
> .Audio 628 USB] on usb-0000:00:14.0-2/input3
>  [116677.281756] usbcore: registered new interface driver snd-usb-audio
> 
>  The following nodes are present in the /dev/snd
> 
> $ ls -l /dev/snd/
> 
> total 0
> 
> drwxr-xr-x 2 root root       60 May 12 11:32 by-id
> 
> drwxr-xr-x 2 root root       60 May 12 11:32 by-path
> 
> crw-rw---- 1 root audio 116,  2 May 12 11:32 controlC1
> 
> crw-rw---- 1 root audio 116,  4 May 12 11:32 pcmC1D0c
> 
> crw-rw---- 1 root audio 116,  3 May 12 11:32 pcmC1D0p
> 
> crw-rw---- 1 root audio 116,  1 May 12 11:32 seq
> 
> crw-rw---- 1 root audio 116, 33 May 12 11:32 timer
> 
> 
> 
> What are all these devices present in /dev/snd
> 
> How do I use it for playing and recording an audio?
> 
> Basically first I want to gain knowledge on set of test cases I can
> run on ALSA and then learn ALSA kernel modules stuff including
> snd_usb_audio mdule.
> 
> So please guide me by providing related documentation/Steps.

ALSA should "just work" with this device, no need to do anything to the
kernel driver.  Does it not work properly for you as-is?

thanks,

greg k-h