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cf1c485 · Mar 8, 2015

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NOTES.md

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Chrome OS Linux kernel command line

Chrome OS uses quite a lot of kernel parameters. So here is the full line as i see it in dmesg after booting into Chrome OS.

cros_secure console= loglevel=7 init=/sbin/init cros_secure oops=panic panic=-1 root=/dev/dm-0 rootwait ro dm_verity.error_behavior=3 dm_verity.max_bios=-1 dm_verity.dev_wait=1 dm="1 vroot none ro 1,0 2506752 verity payload=PARTUUID=XXX/PARTNROFF=1 hashtree=PARTUUID=XXX/PARTNROFF=1 hashstart=2506752 alg=sha1 root_hexdigest=XXX salt=XXX" noinitrd vt.global_cursor_default=0 kern_guid=XXX add_efi_memmap boot=local noresume noswap i915.modeset=1 tpm_tis.force=1 tpm_tis.interrupts=0 nmi_watchdog=panic,lapic iTCO_vendor_support.vendorsupport=3 gpt

Lightbar control

The lightbar on the Pixel can be controlled through EC. The tool for this is ectool which is part of the Chrome OS installation.

Konami code

ectool lightbar seq stop
ectool lightbar seq run

Run the sequence

ectool lightbar seq konami

Stop sequences so you can play with the lightbar

ectool lightbar seq stop

Turn all lights to green

ectool lightbar 4 00 ff 00

Turn the first led to blue

ectool lightbar 0 00 00 ff

Turn the lightbar off

ectool lightbar off

Turn the lightbar on

ectool lightbar on

Start the sequence again and return things to normal

ectool lightbar init
ectool lightbar seq run

To get all this on Linux we need the ectool binary. The source code and details is checked into Chromium OS repository.

There is also a Mainline Kernel patch available which exposes EC lightbar through sysfs. I might add this to my Kernel patches eventually. THis patch has been submitted to the upstream Kernel here. These patches require a modified ectool which seems to be available too.

Building ectool

git clone git://git.collabora.co.uk/git/user/javier/ec.git
cd ec
git checkout mainline-ioctl
make BOARD=link CROSS_COMPILE= HOST_CROSS_COMPILE= build/link/util/ectool
sudo ./build/link/util/ectool version

Controlling the fan with ectool

Once you have ectool built for Linux it can be used to get control on the fan.

sudo ./build/link/util/ectool fanduty 0
sudo ./build/link/util/ectool fanduty 100
sudo ./build/link/util/ectool autofanctrl on

Firmware event log

http://www.chromium.org/chromium-os/developer-information-for-chrome-os-devices/chromebook-pixel