Lost ttyACM0 after failed pacman firmware update

[okazou]

Hi every one,

I have a raspberry pi using Arch Linux, connected to an arduino and collecting data at a remote location. While doing an update through ssh terminal, the raspberry pi frozed. When I finally could get some one to reset power to the unit, I re-entered "pacman -Syu" commend and completed the update.

Pacman log

• [2013-12-23 21:54] [PACMAN] Running 'pacman -Syu'
  [2013-12-23 21:54] [PACMAN] synchronizing package lists
  [2013-12-23 21:54] [PACMAN] starting full system upgrade
  [2013-12-23 21:59] [PACMAN] upgraded coreutils (8.22-1 -> 8.22-2)
  [2013-12-23 21:59] [PACMAN] upgraded cryptsetup (1.6.2-2 -> 1.6.3-1)
  [2013-12-23 21:59] [PACMAN] upgraded curl (7.33.0-3 -> 7.34.0-1)
  [2013-12-23 21:59] [PACMAN] upgraded gdk-pixbuf2 (2.30.1-1 -> 2.30.2-1)
  [2013-12-23 22:00] [PACMAN] upgraded gnutls (3.2.7-1 -> 3.2.8-1)
  [2013-12-23 22:00] [PACMAN] upgraded hwids (20130607-1 -> 20130915.1-1)
  [2013-12-23 22:00] [PACMAN] upgraded libpipeline (1.2.5-1 -> 1.2.6-1)
  [2013-12-24 09:10] [PACMAN] Running 'pacman -Syu'
  [2013-12-24 09:10] [PACMAN] synchronizing package lists
  [2013-12-24 09:10] [PACMAN] starting full system upgrade
  [2013-12-24 09:11] [PACMAN] upgraded lxpolkit (0.1.0-2 -> 0.1.0-3)
  [2013-12-24 09:11] [PACMAN] upgraded systemd (208-2 -> 208-3)
  [2013-12-24 09:12] [PACMAN] upgraded mesa (9.2.5-1 -> 10.0.1-1)
  [2013-12-24 09:12] [PACMAN] upgraded mesa-libgl (9.2.5-1 -> 10.0.1-1)
  [2013-12-24 09:12] [PACMAN] upgraded pcre (8.33-2 -> 8.34-1)
  [2013-12-24 09:12] [PACMAN] upgraded raspberrypi-firmware-bootloader (20131206-1 -> 20131223-1)
  [2013-12-24 09:12] [PACMAN] upgraded raspberrypi-firmware-bootloader-x (20131206-1 -> 20131223-1)
  [2013-12-24 09:12] [PACMAN] upgraded raspberrypi-firmware-emergency-kernel (20131206-1 -> 20131223-1)
  [2013-12-24 09:12] [PACMAN] upgraded raspberrypi-firmware-tools (20131206-1 -> 20131223-1)
  [2013-12-24 09:12] [PACMAN] upgraded systemd-sysvcompat (208-2 -> 208-3)
  [2013-12-24 09:12] [PACMAN] upgraded tzdata (2013h-1 -> 2013i-1)

But now I do not get the ttyACM0 to communicate with the arduino. The journalctl log has no entry between the start of the update and the power reset:

• Dec 23 21:54:41 jmpi sudo[29297]: jm : TTY=pts/0 ; PWD=/home/jm ; USER=root ; COMMAND=/usr/bin/pacman -Syu
  Dec 23 21:54:41 jmpi sudo[29297]: pam_unix(sudo:session): session opened for user root by jm(uid=0)
  -- Reboot -- //power reset of the 24th
  Dec 31 19:00:17 jmpi systemd-journal[65]: Runtime journal is using 120.0K (max 10.4M, leaving 15.6M of free 104.3M, current limit 10.4M).

I can see the arduino information with "lsusb" but /dev do not list the ttyACM0 connection. I have attempted to refresh many package, I search the web, I looked in the arch and raspberry forums, rebooted... did not find any thing yet.

On the first instance of the update sequence, there was 19 pakeges to be updated, now I count only 18 that have been updated and the system never listed the missing one. Is there a way to find what is the missing package, the one that was being processed at the time of the failure?

Any one has a suggestion?

[okazou]

I know I could simply re-install... But it's a great opportunity to learn more about Linux

I made progress : I foud that the drivers in /lib/modules/3.10.25-1-ARCH/kernel/drivers/usb/class/ were corrupted. I am trying to reinstall them. I tried reloading udev and other pakages with no success. On the web, I cannot find which Arch pakage contain

cdc-acm.ko.gz

Help please!

[okazou]

I finally solved this issue through kernel update. The kernel update was the broken update.

Thanks any way.