linux-kernel - [PATCH 14/26] serial: meson: drop low-latency workaround

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Date:   Wed, 21 Apr 2021 11:54:57 +0200
From:   Johan Hovold <johan@...nel.org>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     Jiri Slaby <jirislaby@...nel.org>, linux-serial@...r.kernel.org,
        linux-kernel@...r.kernel.org, Johan Hovold <johan@...nel.org>
Subject: [PATCH 14/26] serial: meson: drop low-latency workaround

The meson driver has always carried an unnecessary workaround for the
infamous low_latency behaviour of tty_flip_buffer_push(), which had
already been removed by the time the driver was added by commit
ff7693d079e5 ("ARM: meson: serial: add MesonX SoC on-chip uart driver").

Specifically, since commit a9c3f68f3cd8 ("tty: Fix low_latency BUG"),
tty_flip_buffer_push() always schedules a work item to push data to the
line discipline and there's no need to keep any low_latency hacks around.

Signed-off-by: Johan Hovold <johan@...nel.org>
---
 drivers/tty/serial/meson_uart.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/drivers/tty/serial/meson_uart.c b/drivers/tty/serial/meson_uart.c
index 69eeef9edfa5..529cd0289056 100644
--- a/drivers/tty/serial/meson_uart.c
+++ b/drivers/tty/serial/meson_uart.c
@@ -226,9 +226,7 @@ static void meson_receive_chars(struct uart_port *port)

 	} while (!(readl(port->membase + AML_UART_STATUS) & AML_UART_RX_EMPTY));

-	spin_unlock(&port->lock);
 	tty_flip_buffer_push(tport);
-	spin_lock(&port->lock);
 }

 static irqreturn_t meson_uart_interrupt(int irq, void *dev_id)
-- 
2.26.3