[Dev] Upgrade linux-libre drops support for FTDI USB Serial Device

[Luke Shumaker]

At Mon, 27 Oct 2014 21:41:12 +0100,
Mono wrote:
> after upgrading linux-libre from 3.16.4 to 3.17.1 (32-bit) my FTDI
> USB Serial Device does not get recognized anymore. Watching
> journalctl -fk under 3.16.4 while plugging the device in and out
> yields the following:
> 
> usb 2-2: new full-speed USB device number 2 using uhci_hcd
> usbcore: registered new interface driver usbserial
> usbcore: registered new interface driver usbserial_generic
> usbserial: USB Serial support registered for generic
> usbcore: registered new interface driver ftdi_sio
> usbserial: USB Serial support registered for FTDI USB Serial Device
> ftdi_sio 2-2:1.0: FTDI USB Serial Device converter detected
> ...
> 
> In the contrary, linux-libre 3.17.1 does not log anything and does
> not provide me with any /dev/ttyUSB0. Comparing the two config.i686
> files did not let me find the cause.

Try manually-loading/checking-if-loaded the following kernel modules:

 - usbcore
 - usbserial
 - ftdi_sio

I've got an ftdi device somewhere at home--I'll see if I can replicate
the issue tonight.

-- 
Happy hacking,
~ Luke Shumaker