On Sat, Nov 23, 2024 at 09:26:51PM +0100, Miroslav Ondra via B4 Relay wrote: > From: Miroslav Ondra <ondra@xxxxxxxxx> > > Use hrtimer instead of udelay and mdelay calls in interrupt > handler to support shared interrupt lines. > Replace simple bool variable rs485_tx_started by 4-state > variable rs485_tx_state. This says what you are doing, not _what_ you are doing. Please fix this up. > > Signed-off-by: Miroslav Ondra <ondra@xxxxxxxxx> > --- > Data loss on serial line was observed during communication through > serial ports ttyAMA1 and ttyAMA2 interconnected via RS485 transcievers. > Both ports are in one BCM2711 (Compute Module CM40) and they share > the same interrupt line. > > The problem is caused by long waiting for tx queue flush in the function > pl011_rs485_tx_stop. Udelay or mdelay are used to wait. > The function is called from the interrupt handler. If multiple devices > share a single interrupt line, late processing of pending interrupts > and data loss may occur. When operation of both devices are synchronous, > collisions are quite often. > > This rework is based on the method used in tty/serial/imx.c > Use hrtimer instead of udelay and mdelay calls. > Replace simple bool variable rs485_tx_started by 4-state variable > rs485_tx_state. This info is great, why not put this in the changelog text instead? thanks, greg k-h
