Comment 32 for bug 1394368

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.