I assume they're not the only ones, but Xiaomi (a major Chinese manufacturer of Android phones sold both in China and globally) hasn't released Linux kernel sources for any devices released in the last seven months [0], and they've released 50+ devices (!) in that time [1].
Has there ever been a successful enforcement (or even an attempted enforcement) of the GPL against a handset manufacturer?
What are the options for handset users to attempt to force them to uphold their obligations?
Why does Google allow them to continue to be part of the Android platform (use Android trademarks, carry built-in support for Google services, etc) while they violate the GPL?
[0] https://github.com/MiCode/Xiaomi_Kernel_OpenSource
[1] https://www.gsmarena.com/xiaomi-phones-80.php