Re: [PATCH] Fix mic sound on Jieli webcam

On Thu, Dec 17, 2020 at 3:12 PM Takashi Iwai tiwai@suse.de wrote:

Thanks.

...

Interface Association:
  bLength                 8
  bDescriptorType        11
  bFirstInterface         2
  bInterfaceCount         2
  bFunctionClass          1 Audio
  bFunctionSubClass       2 Streaming
  bFunctionProtocol       0
  iFunction               5 USB Microphone
Interface Descriptor:

(snip)

...

  AudioStreaming Interface Descriptor:
    bLength                11
    bDescriptorType        36
    bDescriptorSubtype      2 (FORMAT_TYPE)
    bFormatType             1 (FORMAT_TYPE_I)
    bNrChannels             1
    bSubframeSize           2
    bBitResolution         16
    bSamFreqType            1 Discrete
    tSamFreq[ 0]         8000
  Endpoint Descriptor:
    bLength                 9
    bDescriptorType         5
    bEndpointAddress     0x82  EP 2 IN
    bmAttributes            1
      Transfer Type            Isochronous
      Synch Type               None
      Usage Type               Data
    wMaxPacketSize     0x0100  1x 256 bytes
    bInterval               4

It's 4, and the same is set for all sample rates (8000, 16000, 44100, 48000).

If you don't tweak the datainterval, which error do you get? The actual error message should appear before "... xx callbacks suppressed" line.

Without the tweak, only error messages are:

kernel: usb 1-8: current rate 0 is different from the runtime rate 8000 kernel: usb 1-8: current rate 0 is different from the runtime rate 16000 kernel: usb 1-8: current rate 0 is different from the runtime rate 44100 kernel: usb 1-8: current rate 0 is different from the runtime rate 48000 kernel: usb 1-8: Warning! Unlikely big volume range (=4096), cval->res is probably wrong. kernel: usb 1-8: [3] FU [Mic Capture Volume] ch = 1, val = 0/4096/1

but recording from mic at any rate (8000, 16000, 44100, 48000) results in an incomprehensible sound, like Minion voice.

With your patch 'ALSA: usb-audio: Disable sample read check if firmware doesn't give back' error messages have gone away, but result is the same: Minion voice.

Thanks, Marco