This is a note to let you know that I've just added the patch titled serial: pl011: Do not clear RX FIFO & RX interrupt in unthrottle. to the 6.1-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: serial-pl011-do-not-clear-rx-fifo-rx-interrupt-in-un.patch and it can be found in the queue-6.1 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 0aaa13e4e8f03ce7f07b4fb3045a9802ea1ab81b Author: delisun <delisun@xxxxxxxxxxxx> Date: Thu Nov 10 10:01:08 2022 +0800 serial: pl011: Do not clear RX FIFO & RX interrupt in unthrottle. [ Upstream commit 032d5a71ed378ffc6a2d41a187d8488a4f9fe415 ] Clearing the RX FIFO will cause data loss. Copy the pl011_enabl_interrupts implementation, and remove the clear interrupt and FIFO part of the code. Fixes: 211565b10099 ("serial: pl011: UPSTAT_AUTORTS requires .throttle/unthrottle") Signed-off-by: delisun <delisun@xxxxxxxxxxxx> Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20221110020108.7700-1-delisun@xxxxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c index 5b97645be667..aa0bbb7abeac 100644 --- a/drivers/tty/serial/amba-pl011.c +++ b/drivers/tty/serial/amba-pl011.c @@ -1831,8 +1831,17 @@ static void pl011_enable_interrupts(struct uart_amba_port *uap) static void pl011_unthrottle_rx(struct uart_port *port) { struct uart_amba_port *uap = container_of(port, struct uart_amba_port, port); + unsigned long flags; - pl011_enable_interrupts(uap); + spin_lock_irqsave(&uap->port.lock, flags); + + uap->im = UART011_RTIM; + if (!pl011_dma_rx_running(uap)) + uap->im |= UART011_RXIM; + + pl011_write(uap->im, uap, REG_IMSC); + + spin_unlock_irqrestore(&uap->port.lock, flags); } static int pl011_startup(struct uart_port *port)