In this error handling, "transmit_chars_dma" function will call "transmit_chars_pio" once per characters. But "transmit_chars_pio" will continue to send characters while xmit buffer is not empty. Remove this useless loop, one call is sufficient. Signed-off-by: Valentin Caron <valentin.caron@xxxxxxxxxxx> --- drivers/tty/serial/stm32-usart.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c index 788e002688f2..1f89ab0e49ac 100644 --- a/drivers/tty/serial/stm32-usart.c +++ b/drivers/tty/serial/stm32-usart.c @@ -477,7 +477,7 @@ static void stm32_usart_transmit_chars_dma(struct uart_port *port) const struct stm32_usart_offsets *ofs = &stm32port->info->ofs; struct circ_buf *xmit = &port->state->xmit; struct dma_async_tx_descriptor *desc = NULL; - unsigned int count, i; + unsigned int count; if (stm32_usart_tx_dma_started(stm32port)) { if (!stm32_usart_tx_dma_enabled(stm32port)) @@ -542,8 +542,7 @@ static void stm32_usart_transmit_chars_dma(struct uart_port *port) return; fallback_err: - for (i = count; i > 0; i--) - stm32_usart_transmit_chars_pio(port); + stm32_usart_transmit_chars_pio(port); } static void stm32_usart_transmit_chars(struct uart_port *port) -- 2.17.1