[alsa-devel] Mixer regression with usb soundcard

[Takashi Iwai]

On Mon, 18 Dec 2017 20:10:44 +0100,
Mauro Santos wrote:
> 
> On 18-12-2017 17:50, Jaejoong Kim wrote:
> > Mauro,
> > 
> > Could you please try debug patch(I also attach the patch file)?
> 
> With the attached patch I get the following when plugging in the usb dac
> directly to a usb3 port:
> [   54.391539] usb 1-2: new full-speed USB device number 7 using xhci_hcd
> [   54.514996] usb 1-2: device descriptor read/64, error -71
> [   54.849808] input: HiFimeDIY Audio HiFimeDIY DAC as
> /devices/pci0000:00/0000:00:14.0/usb1/1-2/1-2:1.0/0003:1852:7022.0003/input/input20
> [   54.850168] hid-generic 0003:1852:7022.0003: input,hidraw2: USB HID
> v1.00 Device [HiFimeDIY Audio HiFimeDIY DAC] on usb-0000:00:14.0-2/input0
> [   54.950421] usb 1-2: [DEBUG] nameid:0, len:0
> [   54.950426] usb 1-2: [DEBUG] len:3, get_term_name:PCM
> [   54.950429] usb 1-2: [11] SU [PCM] items = 2
> [   54.950985] usbcore: registered new interface driver snd-usb-audio

Hmm, the driver get the supposedly correct name string here, so I see
no flaw, so far.

Could you put the similar debug prints after reverting the commit and
compare?  Or, at minimum, you can enable simply the kernel debug
prints like below:

  % echo "file sound/usb/mixer.c +p" > /sys/kernel/debug/dynamic_debug_control

and re-plug the device.

Also, could you attach the output of "amixer contents" on both working
and non-working kernels?


thanks,

Takashi