[TriEmbed] BBB /dev/video0 issues

Thu Jul 9 10:46:38 CDT 2015

Alex,
I am able to capture 1920x1080 JPEG stills from my webcamera and
BBB... but I do get some kernel usb errors/warnings which are
concerning.

When I plug my Logitech C920 webcam into a BBB running Debian 8.0 I
get the following error message on the console:
  [ 2803.051554] usb 1-1: device v046d p082d is not supported

root at arm:~$ dmesg | tail -n 13
[ 2801.789289] usb 1-1: new high-speed USB device number 2 using musb-hdrc
[ 2803.051554] usb 1-1: device v046d p082d is not supported
[ 2803.057466] usb 1-1: New USB device found, idVendor=046d, idProduct=082d
[ 2803.057506] usb 1-1: New USB device strings: Mfr=0, Product=2, SerialNumber=1
[ 2803.057539] usb 1-1: Product: HD Pro Webcam C920
[ 2803.057571] usb 1-1: SerialNumber: 7F4B4CDF
[ 2803.212104] media: Linux media interface: v0.10
[ 2803.262412] Linux video capture interface: v2.00
[ 2803.476940] uvcvideo: Found UVC 1.00 device HD Pro Webcam C920 (046d:082d)
[ 2803.477450] usbcore: registered new interface driver snd-usb-audio
[ 2803.491667] input: HD Pro Webcam C920 as
/devices/ocp.3/47400000.usb/47401c00.usb/m0
[ 2803.501656] usbcore: registered new interface driver uvcvideo
[ 2803.501685] USB Video Class driver (1.1.1)

root at arm:~$ lsusb
Bus 001 Device 002: ID 046d:082d Logitech, Inc. HD Pro Webcam C920
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

root at arm:~$ uname -a
Linux arm 3.14.26-ti-r43 #1 SMP PREEMPT Tue Dec 23 20:10:13 UTC 2014
armv7l GNU/Linux

root at arm:~$ apt-get install uvccapture uvcdynctrl

root at arm:/tmp# uvccapture -x1920 -y1080
[ 4325.238465] musb_ep_program 896: broken !rx_reinit, ep13 csr 0003
[ 4325.245009] musb_host_rx 1654: RX13 dma busy, csr 2020

root at arm:/tmp# file snap.jpg
snap.jpg: JPEG image data, JFIF standard 1.01, aspect ratio, density
1x1, segment length 16, baseline, precision 8, 1920x1080, frames 3

Bill

On Wed, Jul 8, 2015 at 7:48 PM, Ken via TriEmbed <triembed at triembed.org> wrote:
> BBB has a built in network switch, I have seen data suggesting it should be
> capable of 90Mb/s. I doubt it is the file transfer, unless something else is
> also taking a large chunk of CPU.
> USB cameras will usually do  raw at small resolutions, mjpeg at medium
> resolutions, and newer ones h264 for HD type resolutions.  One thing to
> check might be top, to see what if anything is using great amounts of CPU,
> if you are piping it through ffmpeg or something it could be
> changing/transcoding it underneath you.
> Another would be check to see if the USB camera is being detected/negotiated
> as USB v1 instead of USB v2 which your camera probably is. Not sure but
> lsusb might give you some of that type of info.
>
> Ken
>
>
> -----Original Message----- From: Alex Davis via TriEmbed
> Sent: Wednesday, July 08, 2015 1:33 PM
> To: triembed at triembed.org
> Subject: Re: [TriEmbed] BBB /dev/video0 issues
>
>
> Bill,
>
> I've seen USB issues capturing purely still images and from running
> whatever 'motion' does (max_framerate set to '5' or less).
>
> I was hoping it was some sort of v4l2 lib issue on 3.8 but I've seen it
> on 3.14 as well. I can live with something higher than 3.14 as I am not
> using the GPIO and don't care if overlays work or not.
>
> What I was trying to do, briefly, was run motion and have it drop stills
> to an NFS export where they could be viewed via a web browser. Does the
> BBB hang the ethernet off the USB like the Pi? Maybe there's a bandwidth
> issue? Hard to believe that, since the jpeg files are only about 60 KB.
>
> When I get some more free time, I'll run this with the files saved only
> to the SD card and wrap it in strace.
>
>
> On Wed, Jul 8, 2015, at 01:00 PM, triembed-request at triembed.org wrote:
>>
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>> Today's Topics:
>>
>>    1. Re: BBB USB webcam issues? (Bill Farrow)
>>
>>
>> ----------------------------------------------------------------------
>>
>> Message: 1
>> Date: Wed, 8 Jul 2015 08:27:20 -0400
>> From: Bill Farrow <bill at arrowsreach.com>
>> To: TriEmbed <triembed at triembed.org>
>> Subject: Re: [TriEmbed] BBB USB webcam issues?
>> Message-ID:
>> <CAPm8Nr3QvZNuqh5ntaTw9LubHxcp4qs26Yau=o3aXCE=2ExVVA at mail.gmail.com>
>> Content-Type: text/plain; charset=UTF-8
>>
>> I suspect that it is not a power issue, but a bandwidth or CPU
>> throughput limitation.
>>
>> Note that the Logitech C920 webcam is able to stream h.254 video over
>> USB, which means the data rate is lower than other video encodings and
>> the BBB CPU does not have to do any video compression.
>>
>> Can you capture still images at higher resolutions ?
>>
>> What are you doing with the video stream on the BBB ? Are you
>> processing it, streaming it over the network, writing to flash ? Each
>> one of these will have different resource limitations and potential
>> bottlenecks.
>>
>> Bill
>>
>> On Tue, Jul 7, 2015 at 10:40 PM, Carl Nobile via TriEmbed
>> <triembed at triembed.org> wrote:
>> > Alex,
>> >
>> > Both the BBB and RPi have version 2 USB which specifies 500mA as the >
>> > maximum
>> > allowed current through a USB connector. The max speed of a USB 2 is 480
>> > megabits per second. Here is an interesting addressing some of the issue
>> > > you
>> > mentioned.
>> >
>> > http://electronics.stackexchange.com/questions/24700/why-are-usb-devices-slower-than-480-mbit-s
>> >
>> > Carl
>> >
>> >
>> > On Mon, Jul 6, 2015 at 2:51 PM, Alex Davis via TriEmbed
>> > <triembed at triembed.org> wrote:
>> >>
>> >> Anyone have experience with the BeagleBone Black and USB webcams? In my
>> >> experience with v4l2 and UVC USB webcams on the BBB, getting an image
>> >> above 320x240 is unreliable and 320x240 or below is occasionally
>> >> unreliable. I've seen this on two separate BBBs under 3.8 and 3.14
>> >> kernels. It is more reliable if you set the webcam to send a compressed
>> >> image stream (JPEG) vs uncompressed (YUV), so it makes me think the
>> >> issue is data-rate dependent on the USB bus.
>> >>
>> >> I am using a Microsoft Lifecam Cinema camera. It is rock-solid on my
>> >> Debian laptop running a 3.8 kernel at up to the native 12800x720
>> >> resolution.
>> >>
>> >> I know with the early Raspberry Pi there is an issue with limited USB
>> >> current, but I don't think that's the case with the BBB. I use at
>> >> minimum a 2A 5V supply, which should be plenty for the BBB and the USB
>> >> webcam. Could it be some hardware issue limited to the original 2 GB
>> >> eMMC models that I have?
>> >>
>> >> There isn't much on the web with regards to BBB-specific webcam issues.
>> >> I've seen BBB projects using high-end logitech cameras for live
>> >> streaming, so it must work for some.
>> >>
>> >> --
>> >> "The theater of noise is proof of our potential."
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>> >
>> > --
>> >
>> > -------------------------------------------------------------------------------
>> > Carl J. Nobile (Software Engineer)
>> > carl.nobile at gmail.com
>> >
>> > -------------------------------------------------------------------------------
>> >
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>
>
>
> --
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