This is a note to let you know that I've just added the patch titled serial: fsl_lpuart: disable DMA for console and fix sysrq to the 5.13-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-fsl_lpuart-disable-dma-for-console-and-fix-sy.patch and it can be found in the queue-5.13 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 5d7b3c9c48b8447853b3d550b664eb1cc075fb17 Author: Michael Walle <michael@xxxxxxxx> Date: Wed May 12 16:12:55 2021 +0200 serial: fsl_lpuart: disable DMA for console and fix sysrq [ Upstream commit 8cac2f6eb8548245e6f8fb893fc7f2a714952654 ] SYSRQ doesn't work with DMA. This is because there is no error indication whether a symbol had a framing error or not. Actually, this is not completely correct, there is a bit in the data register which is set in this case, but we'd have to read change the DMA access to 16 bit and we'd need to post process the data, thus make the DMA pointless in the first place. Signed-off-by: Michael Walle <michael@xxxxxxxx> Link: https://lore.kernel.org/r/20210512141255.18277-10-michael@xxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c index 4cad2ac00e9f..0d7ea144a4a6 100644 --- a/drivers/tty/serial/fsl_lpuart.c +++ b/drivers/tty/serial/fsl_lpuart.c @@ -1571,6 +1571,9 @@ static void lpuart_tx_dma_startup(struct lpuart_port *sport) u32 uartbaud; int ret; + if (uart_console(&sport->port)) + goto err; + if (!sport->dma_tx_chan) goto err; @@ -1600,6 +1603,9 @@ static void lpuart_rx_dma_startup(struct lpuart_port *sport) int ret; unsigned char cr3; + if (uart_console(&sport->port)) + goto err; + if (!sport->dma_rx_chan) goto err;