Commit 7a637784d517 ("serial: imx: reduce RX interrupt frequency") introduced a regression on the i.MX6UL EVK board. The issue can be reproduced with the following steps:

- Open vi on the board. - Paste a text file (~150 characters). - Save the file, then repeat the process. - Compare the sha256sum of the saved files.

The checksums do not match due to missing characters or entire lines.

Fix this by restoring the RXTL value to 1 when the UART is used as a console.

This ensures timely RX interrupts and reliable data reception in console mode.

With this change, pasted content is saved correctly, and checksums are always consistent.

Cc: stable@vger.kernel.org Fixes: 7a637784d517 ("serial: imx: reduce RX interrupt frequency") Signed-off-by: Fabio Estevam festevam@gmail.com --- drivers/tty/serial/imx.c | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c index bd02ee898f5d..500dfc009d03 100644 --- a/drivers/tty/serial/imx.c +++ b/drivers/tty/serial/imx.c @@ -235,6 +235,7 @@ struct imx_port { enum imx_tx_state tx_state; struct hrtimer trigger_start_tx; struct hrtimer trigger_stop_tx; + unsigned int rxtl; };

struct imx_port_ucrs { @@ -1339,6 +1340,7 @@ static void imx_uart_clear_rx_errors(struct imx_port *sport)

#define TXTL_DEFAULT 8 #define RXTL_DEFAULT 8 /* 8 characters or aging timer */ +#define RXTL_CONSOLE_DEFAULT 1 #define TXTL_DMA 8 /* DMA burst setting */ #define RXTL_DMA 9 /* DMA burst setting */

@@ -1457,7 +1459,7 @@ static void imx_uart_disable_dma(struct imx_port *sport) ucr1 &= ~(UCR1_RXDMAEN | UCR1_TXDMAEN | UCR1_ATDMAEN); imx_uart_writel(sport, ucr1, UCR1);

- imx_uart_setup_ufcr(sport, TXTL_DEFAULT, RXTL_DEFAULT); + imx_uart_setup_ufcr(sport, TXTL_DEFAULT, sport->rxtl);

sport->dma_is_enabled = 0; } @@ -1482,7 +1484,12 @@ static int imx_uart_startup(struct uart_port *port) return retval; }

- imx_uart_setup_ufcr(sport, TXTL_DEFAULT, RXTL_DEFAULT); + if (uart_console(&sport->port)) + sport->rxtl = RXTL_CONSOLE_DEFAULT; + else + sport->rxtl = RXTL_DEFAULT; + + imx_uart_setup_ufcr(sport, TXTL_DEFAULT, sport->rxtl);

/* disable the DREN bit (Data Ready interrupt enable) before * requesting IRQs @@ -1948,7 +1955,7 @@ static int imx_uart_poll_init(struct uart_port *port) if (retval) clk_disable_unprepare(sport->clk_ipg);

- imx_uart_setup_ufcr(sport, TXTL_DEFAULT, RXTL_DEFAULT); + imx_uart_setup_ufcr(sport, TXTL_DEFAULT, sport->rxtl);

uart_port_lock_irqsave(&sport->port, &flags);

@@ -2040,7 +2047,7 @@ static int imx_uart_rs485_config(struct uart_port *port, struct ktermios *termio /* If the receiver trigger is 0, set it to a default value */ ufcr = imx_uart_readl(sport, UFCR); if ((ufcr & UFCR_RXTL_MASK) == 0) - imx_uart_setup_ufcr(sport, TXTL_DEFAULT, RXTL_DEFAULT); + imx_uart_setup_ufcr(sport, TXTL_DEFAULT, sport->rxtl); imx_uart_start_rx(port); }

@@ -2302,7 +2309,7 @@ imx_uart_console_setup(struct console *co, char *options) else imx_uart_console_get_options(sport, &baud, &parity, &bits);

- imx_uart_setup_ufcr(sport, TXTL_DEFAULT, RXTL_DEFAULT); + imx_uart_setup_ufcr(sport, TXTL_DEFAULT, sport->rxtl);

retval = uart_set_options(&sport->port, co, baud, parity, bits, flow);