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 --- V1 -> V2: align the space,Update code to v6.8-rc3,and make modifications based on it --- sound/usb/mixer.c | 7 +++++++ sound/usb/quirks.c | 2 ++ 2 files changed, 9 insertions(+)

diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c index 409fc1164694..d1bdb0b93bda 100644 --- a/sound/usb/mixer.c +++ b/sound/usb/mixer.c @@ -1211,6 +1211,13 @@ static void volume_control_quirks(struct usb_mixer_elem_info *cval, cval->res = 16; } break; + case USB_ID(0x1bcf, 0x2281): /* HD Webcam */ + if (!strcmp(kctl->id.name, "Mic Capture Volume")) { + usb_audio_info(chip, + "set resolution quirk: cval->res = 16\n"); + cval->res = 16; + } + break; } }

diff --git a/sound/usb/quirks.c b/sound/usb/quirks.c index 09712e61c606..f222532d4d43 100644 --- a/sound/usb/quirks.c +++ b/sound/usb/quirks.c @@ -2185,6 +2185,8 @@ static const struct usb_audio_quirk_flags_table quirk_flags_table[] = { QUIRK_FLAG_ALIGN_TRANSFER), DEVICE_FLG(0x534d, 0x2109, /* MacroSilicon MS2109 */ QUIRK_FLAG_ALIGN_TRANSFER), + DEVICE_FLG(0x1bcf, 0x2281, /* HD Webcam */ + QUIRK_FLAG_GET_SAMPLE_RATE),

/* Vendor matches */ VENDOR_FLG(0x045e, /* MS Lifecam */