Bug#925557: linux-image-4.19.0-4-amd64: kworker CPU hog, abundance of interrupts on PCI-E port with ath9k wireless card

[Vladimir K]

Tried booting into old kernels from Debian Snapshots, down to 
linux-image-4.14.0-2-amd64. Problem persists. Either I just didn't notice it 
before, or the problem originated from something other than kernel.