When upgrading to 5.3 my AP started to work really slow. I tracked the problem to 4504f0e5b5714d9d26b1a80bf1fc133c95830588 and fixed the issue.
Logs before the patch: ath10k_pci 0000:04:00.0: qca988x hw2.0 target 0x4100016c chip_id 0x043222ff sub 0000:0000 ath10k_pci 0000:04:00.0: kconfig debug 1 debugfs 1 tracing 1 dfs 0 testmode 0 ath10k_pci 0000:04:00.0: firmware ver 10.2.4-1.0-00047 api 5 features no-p2p,raw-mode,mfp,allows-mesh-bcast crc32 35bd9258 ath10k_pci 0000:04:00.0: board_file api 1 bmi_id N/A crc32 bebc7c08 ath10k_pci 0000:04:00.0: UART prints enabled Notice that UART prints were enabled (when they were not enabled by param) The attached patch fixes the issue when uart_print is false and uart_pin_workaround also false.
