On Wed, 17 Jul 2024 09:51:49 +0200, wangdicheng wrote:

From: wangdicheng wangdicheng@kylinos.cn

I own an external usb Webcam, HD webcam, which had low mic volume and inconsistent sound quality. Video works as expected.

(snip) [ 95.473820][ 1] [ T73] usb 5-2.2: new high-speed USB device number 7 using xhci_hcd [ 95.773974][ 1] [ T73] usb 5-2.2: New USB device found, idVendor=1bcf, idProduct=2281, bcdDevice= 0.05 [ 95.783445][ 1] [ T73] usb 5-2.2: New USB device strings: Mfr=1, Product=2, SerialNumber=3 [ 95.791872][ 1] [ T73] usb 5-2.2: Product: HD webcam [ 95.797001][ 1] [ T73] usb 5-2.2: Manufacturer: Sunplus IT Co [ 95.802996][ 1] [ T73] usb 5-2.2: SerialNumber: 20200513 [ 96.092610][ 2] [ T3680] usb 5-2.2: Warning! Unlikely big volume range (=4096), cval->res is probably wrong. [ 96.102436][ 2] [ T3680] usb 5-2.2: [5] FU [Mic Capture Volume] ch = 1, val = 0/4096/1

Set up quirk cval->res to 16 for 256 levels, Set GET_SAMPLE_RATE quirk flag to stop trying to get the sample rate. Confirmed that happened anyway later due to the backoff mechanism, After 3 failures.

All audio stream on device interfaces share the same values, apart from wMaxPacketSize and tSamFreq :

  bLength                 9
  bDescriptorType         4
  bInterfaceNumber        3
  bAlternateSetting       4
  bNumEndpoints           1
  bInterfaceClass         1 Audio

Interface Descriptor: bLength 9 bDescriptorType 4 bInterfaceNumber 3 bAlternateSetting 4 bNumEndpoints 1 bInterfaceClass 1 Audio bInterfaceSubClass 2 Streaming bInterfaceProtocol 0 iInterface 0 AudioStreaming Interface Descriptor: bLength 7 bDescriptorType 36 bDescriptorSubtype 1 (AS_GENERAL) bTerminalLink 3 bDelay 1 frames wFormatTag 0x0001 PCM 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] 48000 Endpoint Descriptor: bLength 9 bDescriptorType 5 bEndpointAddress 0x86 EP 6 IN bmAttributes 5 Transfer Type Isochronous Synch Type Asynchronous Usage Type Data wMaxPacketSize 0x0064 1x 100 bytes bInterval 4 bRefresh 0 bSynchAddress 0 AudioStreaming Endpoint Descriptor: bLength 7 bDescriptorType 37 bDescriptorSubtype 1 (EP_GENERAL) bmAttributes 0x01 Sampling Frequency bLockDelayUnits 0 Undefined wLockDelay 0x0000 (snip)

Testing patch provides consistent good sound recording quality and volume range.

(snip) [ 95.473820][ 1] [ T73] usb 5-2.2: new high-speed USB device number 7 using xhci_hcd [ 95.773974][ 1] [ T73] usb 5-2.2: New USB device found, idVendor=1bcf, idProduct=2281, bcdDevice= 0.05 [ 95.783445][ 1] [ T73] usb 5-2.2: New USB device strings: Mfr=1, Product=2, SerialNumber=3 [ 95.791872][ 1] [ T73] usb 5-2.2: Product: HD webcam [ 95.797001][ 1] [ T73] usb 5-2.2: Manufacturer: Sunplus IT Co [ 95.802996][ 1] [ T73] usb 5-2.2: SerialNumber: 20200513 [ 96.110630][ 3] [ T3680] usbcore: registered new interface driver snd-usb-audio [ 96.114329][ 7] [ T3677] usb 5-2.2: Found UVC 1.00 device HD webcam (1bcf:2281) [ 96.167555][ 7] [ T3677] usbcore: registered new interface driver uvcvideo

Signed-off-by: wangdicheng wangdicheng@kylinos.cn

The patch can't be applied cleanly to the latest tree, as the table has been sorted. Could you rebase and resubmit? Also a nitpicking:

--- a/sound/usb/quirks.c +++ b/sound/usb/quirks.c @@ -2179,6 +2179,8 @@ static const struct usb_audio_quirk_flags_table quirk_flags_table[] = { QUIRK_FLAG_FIXED_RATE), DEVICE_FLG(0x1bcf, 0x2283, /* NexiGo N930AF FHD Webcam */ QUIRK_FLAG_GET_SAMPLE_RATE),

• DEVICE_FLG(0x1bcf, 0x2281, /* FHD Webcam */

• 	QUIRK_FLAG_GET_SAMPLE_RATE),
  

Please try to align the space.

thanks,

Takashi