[PATCH v2 01/19] tty: serial: samsung: fix tx_empty() to return TIOCSER_TEMT

From: Tudor Ambarus
Date: Fri Jan 19 2024 - 05:45:54 EST


The core expects for tx_empty() either TIOCSER_TEMT when the tx is
empty or 0 otherwise. s3c24xx_serial_txempty_nofifo() might return
0x4, and at least uart_get_lsr_info() tries to clear exactly
TIOCSER_TEMT (BIT(1)). Fix tx_empty() to return TIOCSER_TEMT.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Tudor Ambarus <tudor.ambarus@xxxxxxxxxx>
---
drivers/tty/serial/samsung_tty.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/tty/serial/samsung_tty.c b/drivers/tty/serial/samsung_tty.c
index 71d17d804fda..6fdb32b83346 100644
--- a/drivers/tty/serial/samsung_tty.c
+++ b/drivers/tty/serial/samsung_tty.c
@@ -987,11 +987,10 @@ static unsigned int s3c24xx_serial_tx_empty(struct uart_port *port)
if ((ufstat & info->tx_fifomask) != 0 ||
(ufstat & info->tx_fifofull))
return 0;
-
- return 1;
+ return TIOCSER_TEMT;
}

- return s3c24xx_serial_txempty_nofifo(port);
+ return s3c24xx_serial_txempty_nofifo(port) ? TIOCSER_TEMT : 0;
}

/* no modem control lines */
--
2.43.0.429.g432eaa2c6b-goog