From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751755AbbCTNev (ORCPT ); Fri, 20 Mar 2015 09:34:51 -0400 Received: from mailout1.w1.samsung.com ([210.118.77.11]:19655 "EHLO mailout1.w1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751222AbbCTNes (ORCPT ); Fri, 20 Mar 2015 09:34:48 -0400 X-AuditID: cbfec7f4-b7f126d000001e9a-8b-550c214e24cb Message-id: <550C21F1.5030404@samsung.com> Date: Fri, 20 Mar 2015 14:34:41 +0100 From: Sylwester Nawrocki User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.1.2 MIME-version: 1.0 To: Javier Martinez Canillas , Robert Baldyga Cc: Greg Kroah-Hartman , Jiri Slaby , Olof Johansson , Doug Anderson , linux-samsung-soc@vger.kernel.org, linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/1] serial: samsung: Clear operation mode on UART shutdown References: <1426246731-13751-1-git-send-email-javier.martinez@collabora.co.uk> In-reply-to: <1426246731-13751-1-git-send-email-javier.martinez@collabora.co.uk> Content-type: text/plain; charset=windows-1252 Content-transfer-encoding: 7bit X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFrrALMWRmVeSWpSXmKPExsVy+t/xa7p+ijyhBk9OM1qcXXaQzaJ58Xo2 i6O/Cyw+/97FanF51xw2ixnn9zFZnFncy25x6vpnNosHh3eyO3B6zG64yOLx9/l1Fo/9c9ew e1w50cTq0bdlFaPHmQVH2D0+b5ILYI/isklJzcksSy3St0vgymh58Yap4CR/xduHl9kbGC/z dDFyckgImEjc2PSWFcIWk7hwbz1bFyMXh5DAUkaJ6Q3LmCGcT4wSb3csYgap4hXQkjhxAaSK k4NFQFXi9ftXTCA2m4ChRO/RPkYQW1QgQuLk3T3sEPWCEj8m32MBsUUEMiT6f2xkARnKLPCX UaL17xSwocIC/hIPuprAmoWA7CvTXoI1cAoESBz7fhMozgHUoCdx/6IWSJhZQF5i85q3zBMY BWYhWTELoWoWkqoFjMyrGEVTS5MLipPScw31ihNzi0vz0vWS83M3MUJi4csOxsXHrA4xCnAw KvHw/tzNHSrEmlhWXJl7iFGCg1lJhNdfgCdUiDclsbIqtSg/vqg0J7X4ECMTB6dUA6P+pJTW hVfSwzirw/LyNXU8o5t+fmA2zlKTfDvDNDOAneVe7yeR3jvzPpYuf5mQILL9hPHkjk2lQu7R Lr9KDI7r75z0Kjfk0A67/JNpTte3XFkosOiPD0eq3OaulP0t+5qthJ7zyy9+dXHa8aiq0q1W rSvfCxTylOpJ1Wqc9Zr6Uv2kZbtdrRJLcUaioRZzUXEiAEJo9H1jAgAA Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 13/03/15 12:38, Javier Martinez Canillas wrote: > Exynos serial ports operate either in a DMA-based or interrupt-based > modes. In DMA-based mode, the UART generates a transfer data request > and a Transmission (Tx) interrupt in interrupt-based mode. > > The Tx IRQ is only unmasked in interrupt-based mode and it was done > in s3c24xx_serial_start_tx(). Commit ba019a3e2ad5 ("serial: samsung: > remove redundant interrupt enabling") removed the IRQ enable on that > function since it is enabled when the mode is set in enable_tx_pio(). > > The problem is that enable_tx_pio() is only called if the port mode > has not been set before but the mode was not cleared on .shutdown(). > > So if the UART was shutdown and then started up again, the mode set > will remain and the Tx IRQ won't be unmasked. > > This caused a hang on at least Exynos5250, Exynos5420 and Exynos5800 > when the system is rebooted or powered off. > > Fixes: ba019a3e2ad5 ("serial: samsung: remove redundant interrupt enabling") > Signed-off-by: Javier Martinez Canillas > --- > > I noticed this issue on an Exynos5250 Snow, Exynos5420 Peach Pit and Exynos > 5800 Peach Pi Chromebooks. This patch fixes the issue on all of them. > > The offending commit landed in v4.0-rc1 so this fix is -rc material. > > drivers/tty/serial/samsung.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/drivers/tty/serial/samsung.c b/drivers/tty/serial/samsung.c > index af821a908720..cf08876922f1 100644 > --- a/drivers/tty/serial/samsung.c > +++ b/drivers/tty/serial/samsung.c > @@ -963,6 +963,7 @@ static void s3c24xx_serial_shutdown(struct uart_port *port) > free_irq(ourport->tx_irq, ourport); > tx_enabled(port) = 0; > ourport->tx_claimed = 0; > + ourport->tx_mode = 0; > } The patch looks good to me, Robert could you comment on that? Reviewed-by: Sylwester Nawrocki -- Thanks, Sylwester