Qualcomm Snapdragon 210 (MSM8909)

MSM8909/APQ8009 (or Snapdragon 210) is a low-end Qualcomm SoC released in 2015. There is a slightly higher clocked variant (CPU cores up to 1.3 GHz) available as Snapdragon 212 and a variant with only two CPUs available as MSM8905 or Qualcomm 205.

USB
Works. You can use USB Networking.

Display
Display seems to work fine on all Snapdragon 210 devices using the downstream kernel. Touchscreen doesn't work on all SD210 devices like LG K7. No workaround found yet for the issue.

Mainline
There is an experimental mainline Linux port available at https://github.com/msm8916-mainline/linux. WiFi, Bluetooth, Modem work. The main open problem is the display, which is quite different from other Qualcomm SoCs (MDP3 instead of MDP4/MDP5) and needs a new driver in Linux. However, this only applies to devices where the display is connected via DSI, as SPI displays on devices like the Nokia 8110 4G (nokia-argon) are already supported in the mainline kernel and work without MDP3.