Commit 33ae787b74fc ("serial: tegra: add support to ignore read") added support for dropping input in case CREAD isn't set, but for PIO the ignore_status_mask wasn't checked until after the character had been put in the receive buffer.

Note that the NULL tty-port test is bogus and will be removed by a follow-on patch.

Fixes: 33ae787b74fc ("serial: tegra: add support to ignore read") Cc: stable stable@vger.kernel.org # 5.4 Cc: Shardar Shariff Md smohammed@nvidia.com Cc: Krishna Yarlagadda kyarlagadda@nvidia.com Signed-off-by: Johan Hovold johan@kernel.org --- drivers/tty/serial/serial-tegra.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/tty/serial/serial-tegra.c b/drivers/tty/serial/serial-tegra.c index 8de8bac9c6c7..b3bbee6b6702 100644 --- a/drivers/tty/serial/serial-tegra.c +++ b/drivers/tty/serial/serial-tegra.c @@ -653,11 +653,14 @@ static void tegra_uart_handle_rx_pio(struct tegra_uart_port *tup, ch = (unsigned char) tegra_uart_read(tup, UART_RX); tup->uport.icount.rx++;

- if (!uart_handle_sysrq_char(&tup->uport, ch) && tty) - tty_insert_flip_char(tty, ch, flag); + if (uart_handle_sysrq_char(&tup->uport, ch)) + continue;

if (tup->uport.ignore_status_mask & UART_LSR_DR) continue; + + if (tty) + tty_insert_flip_char(tty, ch, flag); } while (1); }