linux-kernel - [PATCH 2/8] atmel_serial: Drain console TX shifter before suspending

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <1214817676-30378-3-git-send-email-haavard.skinnemoen@atmel.com>
Date:	Mon, 30 Jun 2008 11:21:10 +0200
From:	Haavard Skinnemoen <haavard.skinnemoen@...el.com>
To:	kernel@...32linux.org
Cc:	linux-kernel@...r.kernel.org,
	Haavard Skinnemoen <haavard.skinnemoen@...el.com>,
	Andrew Victor <linux@...im.org.za>
Subject: [PATCH 2/8] atmel_serial: Drain console TX shifter before suspending

Funny things may happen if we stop the USART clock before the shifter is
empty. Prevent this from happening by waiting until the shifter is
completely drained before allowing suspend to continue.

Signed-off-by: Haavard Skinnemoen <haavard.skinnemoen@...el.com>
Cc: Andrew Victor <linux@...im.org.za>
---
 drivers/serial/atmel_serial.c |    6 ++++++
 1 files changed, 6 insertions(+), 0 deletions(-)

diff --git a/drivers/serial/atmel_serial.c b/drivers/serial/atmel_serial.c
index 5f0414f..6aeef22 100644
--- a/drivers/serial/atmel_serial.c
+++ b/drivers/serial/atmel_serial.c
@@ -1454,6 +1454,12 @@ static int atmel_serial_suspend(struct platform_device *pdev,
 	struct uart_port *port = platform_get_drvdata(pdev);
 	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
 
+	if (atmel_is_console_port(port) && console_suspend_enabled) {
+		/* Drain the TX shifter */
+		while (!(UART_GET_CSR(port) & ATMEL_US_TXEMPTY))
+			cpu_relax();
+	}
+
 	if (device_may_wakeup(&pdev->dev)
 	    && !atmel_serial_clk_will_stop())
 		enable_irq_wake(port->irq);
-- 
1.5.5.4

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/