The integrated webcam with USB identifier 5986:055a does not work properly on my laptop. Although it is powered on and activated in the BIOS it does not appear as /dev/video* and is consequently not recognized by any software. In the log files you will typically find the error message: uvcvideo: No valid video chain found. This particular Acer webcam seems to be used in a variety of Lenovo notebooks, especially ThinkPads, e.g. ThinkPad L450, ThinkPad E455, ThinkPad E550.

Fortunately, there is a patch to the respective kernel module uvcvideo. In the following you will find the steps needed to patch and recompile the uvcvideo module. Now, I am using kernel version 4.7.2-1 on Arch Linux. Make sure to adjust the commands below to your platform.

  • Download and unpack the respective kernel sources from kernel.org:

    cd /usr/src
    wget http://www.kernel.org/pub/linux/kernel/v4.x/linux-4.7.2.tar.xz
    tar xfv linux-4.7.2.tar.xz
    
  • Download and apply the relevant patch:

    cd linux-4.7.2
    wget -O uvc.patch https://launchpadlibrarian.net/262285470/0001-PATCH-v3-uvcvideo-uvc_scan_fallback-for-webcams-with.patch
    patch -p1 < uvc.patch
    
  • Compile the new kernel module:

    cd drivers/media/usb/uvc/
    make -C /lib/modules/$(uname -r)/build M=$(pwd) modules
    
  • If the process was successful we should now have obtained the patched kernel module uvcvideo.ko. We first unload the module uvcvideo and then load the patched version:

    rmmod uvcvideo
    insmod uvcvideo.ko
    
  • Now would be a good time to bring up your favorite webcam software (e.g. Cheese) and find out if the integrated webcam gets recognized properly.

  • If the webcam is working now, we can copy the patched kernel module to our kernel modules and use gzip to compress it.
    cp uvcvideo.ko /lib/modules/$(uname -r)/kernel/drivers/media/usb/uvc
    gzip /lib/modules/$(uname -r)/kernel/drivers/media/usb/uvc/uvcvideo.ko
    

Note that this might not be a good solution for permanent usage. However, it will allow you to be able to use your integrated webcam for now.

Here is the corresponding bug report (for Ubuntu) on Launchpad. Thanks to Henrik Ingo for sharing his patch (post #58).