Re: linux-3.2.12: uvcvideo: ** UNRECOGNIZED: 24 ff 42 49 53 54 00 01 05 02 10 00 00 00 00 00 01 06 b8 0b 02 07 b8 0b 03 08 b8 0b 04 09 4e 20 05 0a b8 0b

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Martin,

On Saturday 31 March 2012 17:07:22 Martin Mokrejs wrote:
> Hi,
>   when inspecting "lsusb -v" output I came across this UNRECOGNIZED message.
> Anything to worry about?
> 
> Bus 001 Device 003: ID 05ca:1820 Ricoh Co., Ltd
> Device Descriptor:
>   bLength                18
>   bDescriptorType         1
>   bcdUSB               2.00
>   bDeviceClass          239 Miscellaneous Device
>   bDeviceSubClass         2 ?
>   bDeviceProtocol         1 Interface Association
>   bMaxPacketSize0        64
>   idVendor           0x05ca Ricoh Co., Ltd
>   idProduct          0x1820
>   bcdDevice            c.27
>   iManufacturer           1 CN01MWM9724871A4KB28A00
>   iProduct                2 Laptop_Integrated_Webcam_FHD
> [cut]
>     Interface Descriptor:
>       bLength                 9
>       bDescriptorType         4
>       bInterfaceNumber        1
>       bAlternateSetting      13
>       bNumEndpoints           1
>       bInterfaceClass        14 Video
>       bInterfaceSubClass      2 Video Streaming
>       bInterfaceProtocol      0
>       iInterface              0
>       Endpoint Descriptor:
>         bLength                 7
>         bDescriptorType         5
>         bEndpointAddress     0x82  EP 2 IN
>         bmAttributes            5
>           Transfer Type            Isochronous
>           Synch Type               Asynchronous
>           Usage Type               Data
>         wMaxPacketSize     0x1400  3x 1024 bytes
>         bInterval               1
>         ** UNRECOGNIZED:  24 ff 42 49 53 54 00 01 05 02 10 00 00 00 00 00 01
> 06 b8 0b 02 07 b8 0b 03 08 b8 0b 04 09 4e 20 05 0a b8 0b

That's a vendor-specific descriptor, as reported by the second byte being 
0xff. Vendor-specific descriptors are not standard (and very often not 
documented), so lsusb doesn't know how to decode it. The uvcvideo driver 
happily ignores it completely.

Such descriptors are used for various purposes, often to add proprietary 
extensions to the device. In this case, as the next 4 bytes decode to 'BIST' 
(most likely Built-In Self Test) in ASCII, I expect the descriptor to be used 
for production and QA purpose.

> It is about the uvcvideo driver I think. The camera works, at least in skype
> so probably I should not bother you asking this question at all. ;-)

Getting a better understanding of Linux is always worth a question :-)

> usb 1-1.5: new high-speed USB device number 3 using ehci_hcd
> usb 1-1.5: skipped 1 descriptor after configuration
> usb 1-1.5: skipped 6 descriptors after interface
> usb 1-1.5: skipped 1 descriptor after endpoint
> usb 1-1.5: skipped 19 descriptors after interface
> usb 1-1.5: skipped 1 descriptor after endpoint
> usb 1-1.5: default language 0x0409
> usb 1-1.5: udev 3, busnum 1, minor = 2
> usb 1-1.5: New USB device found, idVendor=05ca, idProduct=1820
> usb 1-1.5: New USB device strings: Mfr=1, Product=2, SerialNumber=0
> usb 1-1.5: Product: Laptop_Integrated_Webcam_FHD
> usb 1-1.5: Manufacturer: CN01MWM9724871A4KB28A00
> usb 1-1.5: usb_probe_device
> usb 1-1.5: configuration #1 chosen from 1 choice
> usb 1-1.5: adding 1-1.5:1.0 (config #1, interface 0)
> uvcvideo 1-1.5:1.0: usb_probe_interface
> uvcvideo 1-1.5:1.0: usb_probe_interface - got id
> uvcvideo: Found UVC 1.00 device Laptop_Integrated_Webcam_FHD (05ca:1820)
> input: Laptop_Integrated_Webcam_FHD as
> /devices/pci0000:00/0000:00:1a.0/usb1/1-1/1-1.5/1-1.5:1.0/input/input8 usb
> 1-1.5: adding 1-1.5:1.1 (config #1, interface 1)

-- 
Regards,

Laurent Pinchart