[SOLVED] USB DSLR camera not detected

endlesik · 2021-08-14 02:54:16

Hello again!

Some time ago I found this guide - and it worked like a charm!
I've tried to configure it like few months ago, and everything worked without any problems.
I've used my DSLR as a webcam again not so long ago - maybe a month? Max 2. Arch up-to-date. No problems, all I had to do is to change video0 to video2, I think, in my script below.

I've wanted to use it again and it just stopped working. My other webcam works just fine (microsoft one hah), but my OS declines to even detect the DSRL cam via USB..
Here's my script for calling the cam:

gphoto2 --stdout --capture-movie | ffmpeg \
-hwaccel nvdec \
-c:v mjpeg_cuvid \
-i - \
-vcodec rawvideo \
-pix_fmt yuv420p \
-threads 0 \
-f v4l2 /dev/video2

(yes, I've tried each videoX I found within /dev)
I've tried reinstalling packages mentioned in the guide above: gphoto2 v4l-utils v4l2loopback-dkms ffmpeg - and maybe it's zen kernel to blame, but I've checked and v4l module was installed and loaded for zen too, so I doubt it.. Will try on vanilla soon.

I've also tried to force load loopback module with

sudo modprobe v4l2loopback exclusive_caps=1 max_buffers=2

All it did was to create additional videoX device inside of /dev/, but still - arch won't even react to the fact I'm connecting my camera into any USB ports - I've even tried to connect it to the same port of my ms webcam (which works) - OS won't even detect any new connection.. there's nothing in dmesg, nothing in lsusb, lspci - absolutely nothing, no reaction to camera connection (despite the m$ one). I've also tried multiple cam modes, connecting while off, while on etc. - dmesg gives nothing.
Tried multiple ports, cables, and to make it clear - usb in my cam is quite, hm, 'pure'.

GPhoto, which had no problems with detecting my cam, stopped detecting it also (no big surprise, seeing no usb devices being connected, despite the m$ one)

I've tried removing all of videoX from dev, yay'ed for full update, rebooted twice - the cam is still invisible for my pc..

What am I doing wrong? Are there logs that will show me more than dmesg, lsusb and lspci?

What I find quite strange is the fact it still generates more than video0, up to 3, despite no other webcams being detected via USB..

Best regards.

Last edited by endlesik (2021-08-14 15:34:03)

seth · 2021-08-14 08:05:56

Run "dmesg -w" and attach the camera, post the tailing output.
Did you maybe change something in the camera (it can possibly register via mtp, ptp or as storage device and I assume you'll need it in MTP mode)

endlesik · 2021-08-14 14:33:33

Hi, thanks for reply!
As I said - there's nothing in dmesg
Arch completely refuses to recognize my camera being connected to any port.
But it detects everything else without any problems: (I've disconnected and connected my mic, webcam and the cam, while turned on, and off - there's no reaction to the latter whatsoever)

[sie14 16:19] usb 1-3: new full-speed USB device number 4 using xhci_hcd
[  +0,333210] usb 1-3: New USB device found, idVendor=17a0, idProduct=0305, bcdDevice= 2.07
[  +0,000004] usb 1-3: New USB device strings: Mfr=1, Product=2, SerialNumber=0
[  +0,000002] usb 1-3: Product: Samson GoMic
[  +0,000001] usb 1-3: Manufacturer: Samson Technologies
[  +0,200837] input: Samson Technologies Samson GoMic as /devices/pci0000:00/0000:00:01.3/0000:03:00.0/usb1/1-3/1-3:1.3/0003:17A0:0305.0006/input/input26
[  +0,052022] hid-generic 0003:17A0:0305.0006: input,hidraw5: USB HID v1.00 Device [Samson Technologies Samson GoMic] on usb-0000:03:00.0-3/input3
[  +3,125786] usb 1-3: USB disconnect, device number 4
[sie14 16:20] usb 5-2: new high-speed USB device number 3 using xhci_hcd
[  +0,131699] usb 5-2: New USB device found, idVendor=045e, idProduct=0721, bcdDevice= 1.00
[  +0,000005] usb 5-2: New USB device strings: Mfr=1, Product=2, SerialNumber=0
[  +0,000002] usb 5-2: Product: Microsoft LifeCam NX-3000
[  +0,000002] usb 5-2: Manufacturer: Microsoft
[  +0,040756] usb 5-2: Found UVC 1.00 device Microsoft LifeCam NX-3000 (045e:0721)
[  +0,008967] input: Microsoft LifeCam NX-3000: Micr as /devices/pci0000:00/0000:00:08.1/0000:28:00.3/usb5/5-2/5-2:1.0/input/input27
[  +2,088165] usb 5-2: USB disconnect, device number 3

I've changed nothing in the camera (Canon EOS 2000D/Rebel T7 btw.), however I've disabled few modules lately (security):

❯ cat /etc/modprobe.d/blacklist.conf
install rds bin/true
install sctp bin/true
install dccp bin/true
install tipc bin/true
install firewire-core bin/true

I'll try to run Arch on linux kernel and remove the blacklist, maybe they're causing an issue..
I'm unable to find any PTP/MTP options within the cam..

#EDIT
Ok, nothing changed on linux kernel and without the blacklist nothing new appears within dmesg when I try to connect.

Last edited by endlesik (2021-08-14 14:39:45)

seth · 2021-08-14 14:54:05

Cable? Plugs? Does the camera detect the connection to the system (in doubt as power supply)?
No response *at all* when attaching the device would suggest that it isn't attached and the #1 cause for that is still the cable.

endlesik · 2021-08-14 15:33:35

... ok I've figured it out.
It seems like the cam musn't have WiFi enabled to be able to connect to a PC via USB...
I'm quite sure though I used to connect it with WiFi enabled anyways and it had no problem of connecting.. weird.

Well, sorry for wasting your time!

Have a wonderful day and weekend

Arch Linux

#1 2021-08-14 02:54:16

[SOLVED] USB DSLR camera not detected

#2 2021-08-14 08:05:56

Re: [SOLVED] USB DSLR camera not detected

#3 2021-08-14 14:33:33

Re: [SOLVED] USB DSLR camera not detected

#4 2021-08-14 14:54:05

Re: [SOLVED] USB DSLR camera not detected

#5 2021-08-14 15:33:35

Re: [SOLVED] USB DSLR camera not detected

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