Lark Ultimate 7i WIN

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Device Status Modules
Display Working, including backlight xf86-video-intel
Touchscreen Working, but needs copying firmware and calibration, Windows button not working by default silead
Wireless Working
Audio Working (speaker, 3.5 mm jack, HDMI) snd_soc_rt5640
Battery Status Working battery
Camera (front) Not working on stock Arch kernel (as of 5.3), driver removed in 4.18 gc0310
Camera (back) Not working on stock Arch kernel (as of 5.3) ov2680
Bluetooth Working
MicroSD Reader Working, tested with 64GB microSD sdhci
Power Management Sleep seems to work fine, hibernate may need further testing
Accelerometer Working bmc150_accel_*
Hardware Buttons Working soc_button_array gpio_keys

Lark Ultimate 7i WIN is a budget 7" tablet shipping with Windows 8, 8.1 or 10. Android versions are known to exist but were not as popular and less featured than the Windows (WIN) counterparts. There also exist 8", 10" and 11" versions of these tables and versions with 3G modem, featuring different interiors.

Lark Ultimate 7i WIN has Intel Atom Z3735G BayTrail processor with integrated graphics and 1 GB of integrated DDR3L RAM, 16 GB eMMC, 1024 x 600 pixel screen with 10-point touchscreen of unknown resolution and "Windows" button, three hardware buttons (volume up, down and power), basic accelerometer, two cameras (VGA in front, 2 Mpix in the back), microphone, mono speaker, 3.5 mm jack slot, microSD slot, miniHDMI port and one microUSB port (for data and charging). It features InsydeH20 32-bit UEFI BIOS.

Configuration

Installation

This tablet uses 32-bit UEFI despite having 64-bit processor. To install 64-bit system on it, see Unified Extensible Firmware Interface#Booting 64-bit kernel on 32-bit UEFI.

For installation, you will most likely need some kind of USB hub, as you need to have keyboard and boot media connected. Booting from microSD was not tested. Wireless should work with recent Arch boot media.

Warning: Be careful not to turn off USB in BIOS, doing so will require disassembly of the device to reset CMOS to default values.

Touchscreen

For touchscreen to work, firmware is needed. For silead (recommended) driver, copy mssl1680.fw file that was extracted from Windows drivers to /usr/lib/firmware/silead/ directory. Then, Calibrating Touchscreen will be needed. Until a better solution is found, this entry can be added at the bottom of .xinitrc file for relatively usable touchpad:

~/.xinitrc
xinput set-prop "silead_ts' --type=float "Coordinate Transformation Matrix" 4.75 0 -0.02 0 6.7 -0.02 0 0 1

See https://github.com/onitake/gsl-firmware/tree/master/firmware/lark/ulti7iwin and https://github.com/onitake/gsl-firmware/blob/master/README.md for more info.

Accelerometer

/sys/bus/i2c/devices lists a BMA250E device. To see how it works, see

$ cd /sys/bus/i2c/devices/i2c-BMA250E\:00/iio\:device0/
$ watch cat in_accel_*_raw

Broken devices

Camera

According to /sys/bus/i2c/devices, there is an INT0310 device (GalaxyCore GC0310 - Front Camera) and OVTI2680 device (OmniVision OV2680 - Back Camera). Both had a short-lived driver implementation as a part of Linux kernels 4.12–4.17 staging atomisp driver [1], which was later removed. OV2680 is implemented as a standalone driver, but it's not enabled on stock Arch kernel.

Device info

Devices on i2c bus

/sys/bus/i2c/devices

i2c-10EC5640:00 snd_soc_rt5640 Realtek RT5640 - Sound Card
i2c-BMA250E:00 bmc150_accel_* Bosch BMC150 - Accelerometer
i2c-INT0310:00 gc0310 GalaxyCore GC0310 - Front Camera
i2c-INT33F4:00 intel_soc_pmic_i2c Intel I2C Interface
i2c-MSSL1680:00 silead GSL1680 - Silead touchescreen
i2c-OVTI2680:00 ov2680 OmniVision OV2680 - Back Camera