[alsa-devel] Mixer regression with usb soundcard

[Mauro Santos]

On 18-12-2017 19:30, Takashi Iwai wrote:
> 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?
> 

I have compiled a new kernel where I have reverted the commit and I've
added the debug output based on your last debug patch. I attach the
patch that reverts the changes and adds the debug output just in case
anyone wants to do a sanity check on it (don't mind the indentation I
think I botched that).

With the debug patches I get no extra output when echoing to the
dynamic_debug/control file, I guess that's expected.

I attach the dmesg and amixer outputs for the case without revert plus
debug (bad) and revert plus debug (good).

One change does jump out:

bad:  usb 1-2: [11] SU [PCM] items = 2
good: usb 1-2: [11] SU [PCM Capture Source] items = 2

-- 
Mauro Santos
-------------- next part --------------
Simple mixer control 'PCM',0
  Capabilities: pvolume pswitch pswitch-joined
  Playback channels: Front Left - Front Right
  Limits: Playback 0 - 110
  Mono:
  Front Left: Playback 0 [0%] [-55.00dB] [on]
  Front Right: Playback 0 [0%] [-55.00dB] [on]
Simple mixer control 'PCM Capture Source',0
  Capabilities: enum
  Items: 'Line' 'IEC958 In'
  Item0: 'Line'
Simple mixer control 'Line',0
  Capabilities: cvolume cswitch cswitch-joined
  Capture channels: Front Left - Front Right
  Limits: Capture 0 - 104
  Front Left: Capture 0 [0%] [-40.00dB] [off]
  Front Right: Capture 0 [0%] [-40.00dB] [off]
-------------- next part --------------
[   63.600402] usb 1-2: new full-speed USB device number 7 using xhci_hcd
[   63.723739] usb 1-2: device descriptor read/64, error -71
[   64.057506] 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
[   64.057780] 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
[   64.154091] usb 1-2: [DEBUG] nameid:0, len:0
[   64.154095] usb 1-2: [DEBUG] len:3, get_term_name:PCM
[   64.154097] usb 1-2: [11] SU [PCM Capture Source] items = 2
[   64.154495] usbcore: registered new interface driver snd-usb-audio
-------------- next part --------------
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-------------- next part --------------
Simple mixer control 'PCM',0
  Capabilities: pvolume pswitch pswitch-joined enum
  Items: 'Line' 'IEC958 In'
  Item0: 'Line'
  Item1: 'Line'
Simple mixer control 'Line',0
  Capabilities: cvolume cswitch cswitch-joined
  Capture channels: Front Left - Front Right
  Limits: Capture 0 - 104
  Front Left: Capture 0 [0%] [-40.00dB] [off]
  Front Right: Capture 0 [0%] [-40.00dB] [off]
-------------- next part --------------
[   56.317038] usb 1-2: new full-speed USB device number 7 using xhci_hcd
[   56.440424] usb 1-2: device descriptor read/64, error -71
[   56.775327] 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
[   56.775689] 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
[   56.876892] usb 1-2: [DEBUG] nameid:0, len:0
[   56.876896] usb 1-2: [DEBUG] len:3, get_term_name:PCM
[   56.876900] usb 1-2: [11] SU [PCM] items = 2
[   56.877392] usbcore: registered new interface driver snd-usb-audio