I commented on the duplicate because I think the situation is a bit 
different.
This patch simply fixes #1394368, that is, for many people who have the 
0x04ca:0x300d device.

However, the same patch makes the same device enter a disconnect / 
reconnect infinite loop in my specific laptop model (Acer Aspire 
V3è371-31KW). The original poster of the duplicate, #1397885, also has 
an Acer Aspire and might be affected by the same issue (not sure about 
it). Sorry about commenting the duplicate if it was wrong.

On my laptop, the patch makes the firmware load into the device and it 
begins an infinite disconnect/reconnect cycle. The boot makes ages, 
lsusb freezes.

Quoting myself 
(https://bugs.launchpad.net/ubuntu/+source/bluez/+bug/1397885/comments/22) :

"Under your kernel, the whole computer runs unstable. the login manager 
and X won't always start, the system takes ages to start, lsusb feezes 
and I get a log of the following with journalctl -xe.

  mai 02 19:21:00 white kernel: usb 1-5: new full-speed USB device 
number 49 using xhci_hcd
mai 02 19:21:01 white kernel: usb 1-5: New USB device found, 
idVendor=04ca, idProduct=300d
mai 02 19:21:01 white kernel: usb 1-5: New USB device strings: Mfr=0, 
Product=0, SerialNumber=0
mai 02 19:21:01 white kernel: usb 1-5: USB disconnect, device number 49
mai 02 19:21:01 white kernel: usb 1-5: new full-speed USB device number 
50 using xhci_hcd
mai 02 19:21:01 white kernel: usb 1-5: New USB device found, 
idVendor=04ca, idProduct=300d
mai 02 19:21:01 white kernel: usb 1-5: New USB device strings: Mfr=0, 
Product=0, SerialNumber=0
mai 02 19:21:01 white kernel: usb 1-5: USB disconnect, device number 50
mai 02 19:21:01 white kernel: usb 1-5: new full-speed USB device number 
51 using xhci_hcd
mai 02 19:21:02 white kernel: usb 1-5: New USB device found, 
idVendor=04ca, idProduct=300d
mai 02 19:21:02 white kernel: usb 1-5: New USB device strings: Mfr=0, 
Product=0, SerialNumber=0
mai 02 19:21:02 white kernel: usb 1-5: USB disconnect, device number 51
mai 02 19:21:02 white kernel: usb 1-5: new full-speed USB device number 
52 using xhci_hcd
mai 02 19:21:02 white kernel: usb 1-5: New USB device found, 
idVendor=04ca, idProduct=300d
mai 02 19:21:02 white kernel: usb 1-5: New USB device strings: Mfr=0, 
Product=0, SerialNumber=0
mai 02 19:21:02 white kernel: usb 1-5: USB disconnect, device number 52
mai 02 19:21:03 white kernel: usb 1-5: new full-speed USB device number 
53 using xhci_hcd
mai 02 19:21:03 white kernel: usb 1-5: New USB device found, 
idVendor=04ca, idProduct=300d
mai 02 19:21:03 white kernel: usb 1-5: New USB device strings: Mfr=0, 
Product=0, SerialNumber=0
mai 02 19:21:03 white kernel: usb 1-5: USB disconnect, device number 53
mai 02 19:21:03 white kernel: usb 1-5: new full-speed USB device number 
54 using xhci_hcd
mai 02 19:21:03 white kernel: usb 1-5: New USB device found, 
idVendor=04ca, idProduct=300d
mai 02 19:21:03 white kernel: usb 1-5: New USB device strings: Mfr=0, 
Product=0, SerialNumber=0"

I made a workaround which makes the device work by loading the patched 
modules, unload them and load the unpatched ones. The firmware being 
loaded, the unpatched modules are able to drive the device.

I sent a mail to the Bluetooth maintainer's mailing list last month, but 
for some reasons, it might have been unnoticed, I didn't received any reply.

I'm concerned for unexperienced users of this computer getting trouble 
with new kernels. If I can help, don't hesitate to ask me any 
information about by laptop.

Cheers,
Raphaël.