I'd like to donate a MacBook Pro

[Alex Henrie]

Dear kernel developers,

I have a MacBookPro12,1 A1502 with a very annoying problem. Every time
it boots, the screen stays black for about 90 seconds, and the
keyboard is unresponsive for an additional 40 seconds. Both the
internal keyboard and (if present) external USB keyboard are
unresponsive. This is a big problem because I use LUKS full-disk
encryption, and I can't put in the password without the keyboard
working. On every boot, I get something like:

starting version 232

A password is required to access the cryptroot volume:
Enter passphrase for /dev/sda4: [   13.697887] usb 2-3: device not
accepting address 2, error -62
[   24.790929] usb2-3: device not accepting address 3, error -62
[   36.097301] usb2-3: device not accepting address 4, error -62
[   47.403659] usb2-3: device not accepting address 5, error -62
[   47.430395] usb2-port3: unable to enumerate USB device

After the final error message, the keyboard starts working and I can
input my password. The dmesg log contains an additional error,
"xhci_hcd 0000:00:14.0: Timeout while waiting for setup device
command", interspersed with the "device not accepting address" errors.
Resetting the SMC and the NVRAM did not help.

I am confident that this is a common problem because I have found
various other users complaining about it:

https://bbs.archlinux.org/viewtopic.php?pid=1613363#p1613363
https://bbs.archlinux.org/viewtopic.php?pid=1451053#p1451053
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1668105
https://bugzilla.kernel.org/show_bug.cgi?id=115741

Mine is an older MacBook model that is not prohibitively expensive
(about 400 USD). Do any of you think that you can fix this bug? If so,
I would love to set up an identical model with an identical Arch Linux
configuration to my own and send it to you to keep and debug.

-Alex