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[04/26] serial: amba-pl010: drop low-latency workaround

Message ID	20210421095509.3024-5-johan@kernel.org
State	New
Headers	show Return-Path: <linux-serial-owner@kernel.org> From: Johan Hovold <johan@kernel.org> To: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jiri Slaby <jirislaby@kernel.org>, linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org, Johan Hovold <johan@kernel.org>, Russell King <linux@armlinux.org.uk> Subject: [PATCH 04/26] serial: amba-pl010: drop low-latency workaround Date: Wed, 21 Apr 2021 11:54:47 +0200 Message-Id: <20210421095509.3024-5-johan@kernel.org> In-Reply-To: <20210421095509.3024-1-johan@kernel.org> References: <20210421095509.3024-1-johan@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk
Series	tty: drop low-latency workarounds \| expand [00/26] tty: drop low-latency workarounds [01/26] tty: mxser: drop low-latency workaround [02/26] serial: altera_jtaguart: drop low-latency workaround [03/26] serial: altera_uart: drop low-latency workaround [04/26] serial: amba-pl010: drop low-latency workaround [05/26] serial: amba-pl011: drop low-latency workaround [06/26] serial: apbuart: drop low-latency workaround [07/26] serial: ar933x: drop low-latency workaround [08/26] serial: arc_uart: drop low-latency workaround [09/26] serial: atmel_serial: drop low-latency workaround [10/26] serial: bcm63xx: drop low-latency workaround [11/26] serial: icom: drop low-latency workaround [12/26] serial: lpc32xx_hs: drop low-latency workaround [13/26] serial: mcf: drop low-latency workaround [14/26] serial: meson: drop low-latency workaround [15/26] serial: mpc52xx_uart: drop low-latency workaround [16/26] serial: msm_serial: drop low-latency workaround [17/26] serial: owl: drop low-latency workaround [18/26] serial: rda: drop low-latency workaround [19/26] serial: rp2: drop low-latency workaround [20/26] serial: sa1100: drop low-latency workaround [21/26] serial: txx9: drop low-latency workaround [22/26] serial: sifive: drop low-latency workaround [23/26] serial: sunsu: drop low-latency workaround [24/26] serial: timbuart: drop low-latency workaround [25/26] serial: vt8500: drop low-latency workaround [26/26] serial: xilinx_uartps: drop low-latency workaround

Commit Message

Johan Hovold April 21, 2021, 9:54 a.m. UTC

Commit 2389b272168c ("[ARM] 4417/1: Serial: Fix AMBA drivers locking")
worked around the infamous low_latency behaviour of
tty_flip_buffer_push() by simply dropping and reacquiring the port lock
in the interrupt handler.

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.

Cc: Russell King <linux@armlinux.org.uk>
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/tty/serial/amba-pl010.c | 2 --
 1 file changed, 2 deletions(-)

diff mbox series

Patch

diff --git a/drivers/tty/serial/amba-pl010.c b/drivers/tty/serial/amba-pl010.c
index 3f96edfe569c..e744b953ca34 100644
--- a/drivers/tty/serial/amba-pl010.c
+++ b/drivers/tty/serial/amba-pl010.c
@@ -159,9 +159,7 @@  static void pl010_rx_chars(struct uart_amba_port *uap)
 	ignore_char:
 		status = readb(uap->port.membase + UART01x_FR);
 	}
-	spin_unlock(&uap->port.lock);
 	tty_flip_buffer_push(&uap->port.state->port);
-	spin_lock(&uap->port.lock);
 }
 
 static void pl010_tx_chars(struct uart_amba_port *uap)