67f2807608
commit 74dba240881820b46b9b1c62ef4de3bfff47fbd4 upstream.
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>
Cc: <stable@vger.kernel.org>
Link: https://patch.msgid.link/20240719020906.8078-1-wangdich9700@163.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.