This is a note to let you know that I've just added the patch titled serial: sprd: Add clearing break interrupt operation to the 5.4-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-sprd-add-clearing-break-interrupt-operation.patch and it can be found in the queue-5.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From abeb2e9414d7e3a0d8417bc3b13d7172513ea8a0 Mon Sep 17 00:00:00 2001 From: Yonghan Ye <yonghan.ye@xxxxxxxxxx> Date: Wed, 4 Dec 2019 20:00:07 +0800 Subject: serial: sprd: Add clearing break interrupt operation From: Yonghan Ye <yonghan.ye@xxxxxxxxxx> commit abeb2e9414d7e3a0d8417bc3b13d7172513ea8a0 upstream. A break interrupt will be generated if the RX line was pulled low, which means some abnomal behaviors occurred of the UART. In this case, we still need to clear this break interrupt status, otherwise it will cause irq storm to crash the whole system. Fixes: b7396a38fb28 ("tty/serial: Add Spreadtrum sc9836-uart driver support") Signed-off-by: Yonghan Ye <yonghan.ye@xxxxxxxxxx> Cc: stable <stable@xxxxxxxxxxxxxxx> Signed-off-by: Baolin Wang <baolin.wang7@xxxxxxxxx> Link: https://lore.kernel.org/r/925e51b73099c90158e080b8f5bed9b3b38c4548.1575460601.git.baolin.wang7@xxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/tty/serial/sprd_serial.c | 3 +++ 1 file changed, 3 insertions(+) --- a/drivers/tty/serial/sprd_serial.c +++ b/drivers/tty/serial/sprd_serial.c @@ -679,6 +679,9 @@ static irqreturn_t sprd_handle_irq(int i if (ims & SPRD_IMSR_TIMEOUT) serial_out(port, SPRD_ICLR, SPRD_ICLR_TIMEOUT); + if (ims & SPRD_IMSR_BREAK_DETECT) + serial_out(port, SPRD_ICLR, SPRD_IMSR_BREAK_DETECT); + if (ims & (SPRD_IMSR_RX_FIFO_FULL | SPRD_IMSR_BREAK_DETECT | SPRD_IMSR_TIMEOUT)) sprd_rx(port); Patches currently in stable-queue which might be from yonghan.ye@xxxxxxxxxx are queue-5.4/serial-sprd-add-clearing-break-interrupt-operation.patch