after updating to 4.14.32 (latest firmware), OpenCV 3.4 open USB camera timeout

[imkow]

after updating to this commit: https://github.com/Hexxeh/rpi-firmware/commit/0382fa9aae15a1641e4c52ba2ffdaf2cfbe0c4f8

4.14.31 is OK.

detailed info:

select timeout select timeout OpenCV Error: Assertion failed (total() == 0 || data != null) in Mat, file /home/pi/projects/opencv-3.4.0/modules/core/include/opencv2/core/mat.inl.hpp, line 500 terminate called after throwing an instance of 'cv::Exception' what(): /home/pi/projects/opencv-3.4.0/modules/core/include/opencv2/core/mat.inl.hpp:500: error: (-215) total() == 0 || data != null in function Mat

[popcornmix]

Please report output of lsusb and lsmod after booting with camera connected.

[imkow]

this is from downgraded 4.14.31 kernel:

pi@raspberrypi:~ $ lsusb
Bus 001 Device 004: ID 045e:0811 Microsoft Corp. 
Bus 001 Device 003: ID 0424:ec00 Standard Microsystems Corp. SMSC9512/9514 Fast Ethernet Adapter
Bus 001 Device 002: ID 0424:9514 Standard Microsystems Corp. SMC9514 Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

pi@raspberrypi:~ $ lsmod 
Module                  Size  Used by
fuse                  106496  3
rfcomm                 49152  6
bnep                   20480  2
hci_uart               24576  1
evdev                  24576  0
bluetooth             368640  28 hci_uart,bnep,rfcomm
ecdh_generic           28672  1 bluetooth
binfmt_misc            20480  1
snd_soc_wm8804_i2c     16384  0
arizona_spi            16384  0
snd_soc_wm8804         16384  1 snd_soc_wm8804_i2c
arizona_ldo1           16384  0
uvcvideo               90112  0
videobuf2_vmalloc      16384  1 uvcvideo
videobuf2_memops       16384  1 videobuf2_vmalloc
videobuf2_v4l2         24576  1 uvcvideo
videobuf2_core         45056  2 uvcvideo,videobuf2_v4l2
videodev              184320  3 uvcvideo,videobuf2_core,videobuf2_v4l2
snd_usb_audio         172032  0
media                  32768  2 uvcvideo,videodev
snd_hwdep              16384  1 snd_usb_audio
snd_usbmidi_lib        32768  1 snd_usb_audio
snd_rawmidi            32768  1 snd_usbmidi_lib
snd_seq_device         16384  1 snd_rawmidi
brcmfmac              307200  0
brcmutil               16384  1 brcmfmac
cfg80211              573440  1 brcmfmac
rfkill                 28672  6 bluetooth,cfg80211
snd_soc_rpi_cirrus     24576  0
snd_soc_bcm2835_i2s    16384  0
snd_bcm2835            32768  1
snd_soc_core          188416  3 snd_soc_wm8804,snd_soc_rpi_cirrus,snd_soc_bcm2835_i2s
snd_compress           20480  1 snd_soc_core
snd_pcm_dmaengine      16384  1 snd_soc_core
snd_pcm                98304  7 snd_soc_wm8804,snd_soc_rpi_cirrus,snd_usb_audio,snd_pcm_dmaengine,snd_soc_bcm2835_i2s,snd_bcm2835,snd_soc_core
snd_timer              32768  1 snd_pcm
snd                    69632  13 snd_compress,snd_hwdep,snd_soc_rpi_cirrus,snd_usb_audio,snd_timer,snd_rawmidi,snd_usbmidi_lib,snd_seq_device,snd_bcm2835,snd_soc_core,snd_pcm
i2c_bcm2835            16384  0
spi_bcm2835            16384  0
uio_pdrv_genirq        16384  0
uio                    20480  1 uio_pdrv_genirq
fixed                  16384  0
i2c_dev                16384  0
ip_tables              24576  0
x_tables               28672  1 ip_tables
ipv6                  434176  26

[JamesH65]

@imkow Is this still an issue with later kernels? (We are currently on 4.14.39 if you use rpi-update)

[jruizaranguren]

I am getting the same error with last kernel version 4.14.41-v7+.

select timeout
select timeout
OpenCV(3.4.1) Error: Assertion failed (total() == 0 || data != __null) in Mat, file /home/pi/opencv-3.4.1/modules/core/include/opencv2/core/mat.inl.hpp, line 500

[6by9]

Further debug required to have any hope of tracking this down. sudo apt install v4l-utils v4l2-ctl -D v4l2-ctl --list-formats-ext v4l2-ctl -V v4l2-ctl -stream-mmap=3 --stream-count=1000 --stream-to=/dev/null That last one should stream 1000 frames from the webcam (ditching the resulting data). If that works then it implies OpenCV is doing something wrong.

There's no obvious changes in the history for USB or V4L2 between 4.14.31 and 4.14.32, other than https://github.com/raspberrypi/linux/commit/8960ba68b681a62a523cc593773d5d03a413a075, but that should only be fixing an initialisation error.

[jruizaranguren]

In my case, this did the trick:

sudo rmmod uvcvideo
sudo modprobe uvcvideo nodrop=1 timeout=5000

[JamesH65]

@6by9 Do we need to increase a default timeout somewhere, as per the previous comment?

[6by9]

timeout defaults to 5000 anyway. https://elixir.bootlin.com/linux/v4.14.52/source/drivers/media/usb/uvc/uvcvideo.h#L171 https://elixir.bootlin.com/linux/v4.14.52/source/drivers/media/usb/uvc/uvc_driver.c#L39

nodrop has the description of "Don't drop incomplete frames". If nodrop!=0, then the uvc queue gets a UVC_QUEUE_DROP_CORRUPTED flag applied, and if we get errors reported then the buffer is reused rather than returned. Getting errors would imply the USB camera is misbehaving at some level, so it should NOT be on by default.

Looking back at the original report, there's the outside chance of a USB regression within the 4.14.31 to 4.14.32 window, but unlikely. If @imkow reports back with the actual model information of his webcam, and whether nodrop=1 works for him, then it gives something that can be investigated.

[JamesH65]

@imkow Can you provide some more information on the HW being used and try the nodrop=1 option outlined above? We won't be able to make any progress unless we get this information.

[nguyen13]

I'm facing the same problem. Did you fix this problem?

[pelwell]

Which kernel are you running? Can you provide the information and follow the suggestion that James mentions above? (@imkow seems to have lost interest)

[nguyen13]

I am using 4.14.71-v7+. I already did the suggestion from @jruizaranguren but the error still there. Opencv version : 3.4.1

[pelwell]

Which hardware are you using?

[6by9]

Have you tried the steps using v4l2-ctl in https://github.com/raspberrypi/linux/issues/2490#issuecomment-390604528 ? Has this device every worked on any Linux platform?

[nguyen13]

I am using Raspberry Pi 3 B+. I already uninstall OpenCv 3.4.1 and install 3.3.0 instead. It seems working normally now. Thanks guys

[6by9]

@nguyen13 Please will you post the output of the requested commands. Downgrading may sort you out for now, but problems ought to be reported back to the OpenCV folk so that they can investigate and fix it. (AFAICT this isn't a Pi issue, but can't say that for certain based on the information given).