Acer C720 ElementaryOS Touchpad Fix

acer-c720-elementaryos-touchpad-fix.md

Lots of folks note how Kernel 3.17 is supposed to fix trackpad issues. So, I initially installed 3.18 and found that my sound didn't work (? YMMV). Indeed, my trackpad did work, but my sound didn't. I then reinstalled elementary via elementaryos-chromebook and didn't update the kernel. Not updating the Kernel is reccommended:

http://shnatsel.blogspot.com/2013/12/why-you-should-not-upgrade-kernel-on.html

Here's what I did to get things working:

1. Installed elementaryos-chromebook
2. Booted into Elementary via Ctrl + L. Went through prompts.
3. Went to Applications > Update Manager. Installed all updates.

• Installed Hardware updates first. Rebooted.
• Then installed software updates. Rebooted.

4. Touchpad still didnt work. At this point, running uname -r in terminal returns 3.13.0-43.
5. I followed the first part of step 5 from the following URL to get the touchpad to work:

• http://realityequation.net/installing-elementary-os-on-an-hp-chromebook-14
• NOTE: You'll notice the author of that post installed 3.12.5-trusty whereas, if you installed all your updates, you'll already be past that version.
• NOTE 2: In light of this, I changed anywhere it said linux-3.12.5 to linux-3.13.11.
• I then ran the script by cding into the directory and typing bash cron-haswell-modules.sh and rebooted.
• Touchpad works.
  • I didn't have to adjust the sensitivity as the second part of step 5 notes.

6. The last thing I did was bind the Volume up and down buttons. Go to System Settings > Keyboard > Media > Volume Up/Down.

cron-haswell-modules.sh

# Create a temp directory for our work
tempbuild=`mktemp -d`
cd $tempbuild

# Determine kernel version (with and without Ubuntu-specific suffix)
mykern=${1:-$(uname -r)}
mykernver=linux-$(echo $mykern | cut -d'-' -f 1)

# Install necessary deps to build a kernel
sudo apt-get build-dep -y --no-install-recommends linux-image-$mykern

# Grab Ubuntu kernel source
wget https://www.kernel.org/pub/linux/kernel/v3.x/linux-3.13.11.tar.xz
tar -xJf linux-3.13.11.tar.xz
cd linux-3.13.11

if [ -f drivers/platform/x86/chromeos_laptop.c ]; then
  platform_folder=x86
elif [ -f drivers/platform/chrome/chromeos_laptop.c ]; then
  platform_folder=chrome
fi

# Use Benson Leung's post-Pixel Chromebook patches:
# https://patchwork.kernel.org/bundle/bleung/chromeos-laptop-deferring-and-haswell/
for patch in 3078491 3078481 3074391 3074441 3074421 3074401 3074431 3074411; do
  wget -O - https://patchwork.kernel.org/patch/$patch/raw/ \
  | sed "s/drivers\/platform\/x86\/chromeos_laptop.c/drivers\/platform\/$platform_folder\/chromeos_laptop.c/g" \
  | patch -p1
done

# Need this
cp /usr/src/linux-headers-$mykern/Module.symvers .

# Prep tree
cp /boot/config-$mykern ./.config
make oldconfig
make prepare
make modules_prepare

# Build only the needed directories
make SUBDIRS=drivers/platform/$platform_folder modules
make SUBDIRS=drivers/i2c/busses modules

# switch to using our new chromeos_laptop.ko module
# preserve old as .orig
sudo mv /lib/modules/$mykern/kernel/drivers/platform/$platform_folder/chromeos_laptop.ko /lib/modules/$mykern/kernel/drivers/platform/$platform_folder/chromeos_laptop.ko.orig
sudo cp drivers/platform/$platform_folder/chromeos_laptop.ko /lib/modules/$mykern/kernel/drivers/platform/$platform_folder/

# switch to using our new designware i2c modules
# preserve old as .orig
sudo mv /lib/modules/$mykern/kernel/drivers/i2c/busses/i2c-designware-core.ko /lib/modules/$mykern/kernel/drivers/i2c/busses/i2c-designware-core.ko.orig
sudo mv /lib/modules/$mykern/kernel/drivers/i2c/busses/i2c-designware-pci.ko /lib/modules/$mykern/kernel/drivers/i2c/busses/i2c-designware-pci.ko.orig
sudo mv /lib/modules/$mykern/kernel/drivers/i2c/busses/i2c-designware-platform.ko /lib/modules/$mykern/kernel/drivers/i2c/busses/i2c-designware-platform.ko.orig
sudo cp drivers/i2c/busses/i2c-designware-*.ko /lib/modules/$mykern/kernel/drivers/i2c/busses/
sudo depmod -a $mykern
echo "Finished building Chromebook modules in $tempbuild. Reboot to use them."