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HATs and other add-ons • Re: Unable to make 2 USB cameras work

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In the command window lsusb shows:
Bus 003 Device 002: ID 1415:2000 Nam Tai E&E Products Ltd. or OmniVision Technologies,
Inc. Sony Playstation Eye
This is not enough. Look here at my Logitech C910 Webcam, which is known to work with Linux, Mac and Windows without installing any driver software:

Code:

Bus 001 Device 014: ID 046d:0821 Logitech, Inc. HD Webcam C910
This tells me that the device is recognized by the USB stack, but not if it's supported. I need to dig deeper with the -v option.

Code:

lsusb -v -s 1:14Bus 001 Device 014: ID 046d:0821 Logitech, Inc. HD Webcam C910Couldn't open device, some information will be missingDevice Descriptor:  bLength                18  bDescriptorType         1  bcdUSB               2.00  bDeviceClass          239 Miscellaneous Device  bDeviceSubClass         2  bDeviceProtocol         1 Interface Association  bMaxPacketSize0        64  idVendor           0x046d Logitech, Inc.  idProduct          0x0821 HD Webcam C910  bcdDevice            0.10  iManufacturer           0  iProduct                0  iSerial                 1 7D90C5E0  bNumConfigurations      1  Configuration Descriptor:    bLength                 9    bDescriptorType         2    wTotalLength       0x0cc1    bNumInterfaces          4    bConfigurationValue     1    iConfiguration          0    bmAttributes         0x80      (Bus Powered)    MaxPower              500mA    […]    Interface Association:      bLength                 8      bDescriptorType        11      bFirstInterface         2      bInterfaceCount         2      [b]bFunctionClass         14 Video[/b]      bFunctionSubClass       3 Video Interface Collection      bFunctionProtocol       0      iFunction               0    Interface Descriptor:      bLength                 9      bDescriptorType         4      bInterfaceNumber        2      bAlternateSetting       0      bNumEndpoints           1      bInterfaceClass        14 Video      bInterfaceSubClass      1 Video Control      bInterfaceProtocol      0      iInterface              0      […]
There are somme 100 lines of output here. The important line is "bFunctionClass 14 Video". This tells me and the OS that this camera is a standard USB Video Camera device, and Linux has drivers for that. There are other devices that only say "255 Unknown/Custom" here. These need special drivers and software that may or may not be present.

The PI libcamera software stack only supports suitable CSI2 cameras. You can't use that with others. Use V4L2 tools with UVC cameras.

And: Yes, CSI2 cable length is limited to 20…30cm. Even if you manged to buy a 1m cable it would just have been a waste of money.

Statistics: Posted by fchk — Mon Apr 21, 2025 6:26 pm



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