virtualbox.org

Hello,

On another machine with a similar setup, I have a win8.1 guest on f21 host, and webcam worked with passthrough after upgrading vbox extensions.

However, on my dell 5520 laptop, with win 7 guest and integrated webcam, I get nothing but black screen on passthrough(after selecting devices/webcams).

If I directly connect to the webcam under devices/usb devices, it works, but is horribly slow.

How do I fix the black screen issue?

BTW, I tried plugging in the USB webcam from the first computer to the laptop and using it passthrough instead of the integrated one passthrough, and it works fine. Why would the integrated one have the problem?

I don't use webcams (or USB anything) in my guests much, but a quick thought: Doesn't a USB device have to be plugged in after the guest is running for Virtualbox to redirect the USB device to the guest instead of the host? (Someone please let me know if this is not true)

Howdy, do you have to do the same on your other working guest, unplug and re-plug-in your webcam after your guest boots, to get the webcam to work properly in the good guest? If so, I'd suppose the fact that the integrated webcam can't be unplugged and replugged, might mean it can't trigger the Virtualbox process to take it from the host and put it properly in the guest.

what is the OS on the second (slow) machine?
attach the vbox.log for your Windows 7 guest. You should also edit your title to Win 7 instead of Win 8.1.

loukingjr wrote:what is the OS on the second (slow) machine?
attach the vbox.log for your Windows 7 guest. You should also edit your title to Win 7 instead of Win 8.1.

Sorry, you are correct that this is win 7. It's Fedora 21 64bit/win 7. USB webcam works fine, logitech c615, but the integrated one is black unless I direct, and then it's very slow if I do it correct.

Attached is log.

Also, webcam light comes on, it's just a black screen.

Your log is somewhat confusing to me anyway. It says you have a Intel Core i5-3570 which has 4 cores and 4 threads (no hyperthreading). But the log also says the host only has 2 cores with 4 threads. The guest is assigned 2 cores which if the host only has 2 cores is a problem if it has 4 not so much. It might be because you aren't using the official version of VirtualBox but the RPMFusion version. I think I need to let someone else take a look at your log.

Thanks for the reply. I was previously using the official version, but having same problem.

In settings, I had set it to 2 cores. Should I set it to 4? I just didn't want to slow down the computer too much.


BTW, here's other info:

dmesg |grep uvcvideo
[ 29.421062] uvcvideo: Found UVC 1.00 device Laptop_Integrated_Webcam_HD (0c45:648d)
[ 29.446907] usbcore: registered new interface driver uvcvideo
[ 699.662649] uvcvideo: Found UVC 1.00 device HD Webcam C615 (046d:082c)


The second one I plugged in, c615, worked fine. The first one gives me just a black screen, but works fine in Linux host.

scottgus1 wrote:I don't use webcams (or USB anything) in my guests much, but a quick thought: Doesn't a USB device have to be plugged in after the guest is running for Virtualbox to redirect the USB device to the guest instead of the host? (Someone please let me know if this is not true)

Howdy, do you have to do the same on your other working guest, unplug and re-plug-in your webcam after your guest boots, to get the webcam to work properly in the good guest? If so, I'd suppose the fact that the integrated webcam can't be unplugged and replugged, might mean it can't trigger the Virtualbox process to take it from the host and put it properly in the guest.

The same C615 works on both machines, plugged into host, Linux, before the guest is turned on.