On Fri, 24 Mar 2023, Stefan Wahren wrote: > Hi, > > after switching to Linux 6.1.21 on our Tarragon board (i.MX6ULL SoC), we > experience the following issues with the debug UART (115200 baud, 8N1, no > hardware flow control): > > - overrun errors if we paste in multiple text lines while system is idle > - no reaction to single key strokes while system is on higher load > > After reverting 7a637784d517 ("serial: imx: reduce RX interrupt frequency") > the issue disappear. > > Maybe it's worth to mention that the Tarragon board uses two additional > application UARTs with similiar baud rates (9600 - 115200 baud, no hardware > flow control) for RS485 communication, but there are no overrun errors (with > and without the mention change). This has come up earlier, see e.g.: https://lore.kernel.org/linux-serial/20221003110850.GA28338@xxxxxxxxxxxxxxxxxxxxxxxxxxxx/ My somewhat uninformed suggestion: if the overrun problems mostly show up with console ports, maybe the trigger level could depend on the port being a console or not? -- i.