From: Jonas Gorski Date: Sun, 3 Mar 2024 15:08:07 +0000 (+0100) Subject: serial: core: only stop transmit when HW fifo is empty X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=7bfb915a597a301abb892f620fe5c283a9fdbd77;p=linux.git serial: core: only stop transmit when HW fifo is empty If the circular buffer is empty, it just means we fit all characters to send into the HW fifo, but not that the hardware finished transmitting them. So if we immediately call stop_tx() after that, this may abort any pending characters in the HW fifo, and cause dropped characters on the console. Fix this by only stopping tx when the tx HW fifo is actually empty. Fixes: 8275b48b2780 ("tty: serial: introduce transmit helpers") Cc: stable@vger.kernel.org Signed-off-by: Jonas Gorski Link: https://lore.kernel.org/r/20240303150807.68117-1-jonas.gorski@gmail.com Signed-off-by: Greg Kroah-Hartman --- diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h index 55b1f3ba48ac1..bb0f2d4ac62f6 100644 --- a/include/linux/serial_core.h +++ b/include/linux/serial_core.h @@ -786,7 +786,8 @@ enum UART_TX_FLAGS { if (pending < WAKEUP_CHARS) { \ uart_write_wakeup(__port); \ \ - if (!((flags) & UART_TX_NOSTOP) && pending == 0) \ + if (!((flags) & UART_TX_NOSTOP) && pending == 0 && \ + __port->ops->tx_empty(__port)) \ __port->ops->stop_tx(__port); \ } \ \