From mboxrd@z Thu Jan 1 00:00:00 1970 From: "gregkh@linuxfoundation.org" Subject: Re: [PATCH v3] serial: mvebu-uart: fix tx lost characters Date: Thu, 22 Mar 2018 18:35:29 +0100 Message-ID: <20180322173529.GA24597@kroah.com> References: <3B588D51285A4A4D8D39C94212E07826279E39@SPQCMBX02.exfo.com> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit Return-path: Content-Disposition: inline In-Reply-To: <3B588D51285A4A4D8D39C94212E07826279E39@SPQCMBX02.exfo.com> Sender: stable-owner@vger.kernel.org To: Gabriel Matni Cc: Miquel Raynal , "linux-serial@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "stable@vger.kernel.org" , =?iso-8859-1?Q?Gr=E9gory?= Clement , Thomas Petazzoni List-Id: linux-serial@vger.kernel.org On Tue, Mar 20, 2018 at 04:09:38PM +0000, Gabriel Matni wrote: > From: Gabriel Matni > > Fixes missing characters on kernel console at low baud rates (i.e.9600). > The driver should poll TX_RDY or TX_FIFO_EMP instead of TX_EMP to ensure > that the transmitter holding register (THR) is ready to receive a new byte. > > TX_EMP tells us when it is possible to send a break sequence via > SND_BRK_SEQ. While this also indicates that both the THR and the TSR are > empty, it does not guarantee that a new byte can be written just yet. > > Fixes: 30530791a7a0 ("serial: mvebu-uart: initial support for Armada-3700 serial port") > Reviewed-by: Miquel Raynal > Acked-by: Gregory CLEMENT > Signed-off-by: Gabriel Matni > --- > Changes since v2: > - use one line for the "Fixes" entry > - removed trailing space between Signed-off-by entry and --- > - start using versioning, previous fixes in v1 > > Changes since v1: > - patch was corrupt, could not be applied > - fixed line indent > --- > drivers/tty/serial/mvebu-uart.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/tty/serial/mvebu-uart.c b/drivers/tty/serial/mvebu-uart.c > index a100e98259d7..f0df0640208e 100644 > --- a/drivers/tty/serial/mvebu-uart.c > +++ b/drivers/tty/serial/mvebu-uart.c > @@ -618,7 +618,7 @@ static void wait_for_xmitr(struct uart_port *port) > u32 val; > > readl_poll_timeout_atomic(port->membase + UART_STAT, val, > - (val & STAT_TX_EMP), 1, 10000); > + (val & STAT_TX_RDY(port)), 1, 10000); > } > > static void mvebu_uart_console_putchar(struct uart_port *port, int ch) > -- > 2.7.4 > > > > -----Original Message----- > > From: gregkh@linuxfoundation.org > > Sent: March 20, 2018 5:32 AM > > To: Gabriel Matni > > Cc: Miquel Raynal ; linux- > > serial@vger.kernel.org; linux-arm-kernel@lists.infradead.org; > > stable@vger.kernel.org; Grégory Clement ; > > Thomas Petazzoni > > Subject: Re: [PATCH] serial: mvebu-uart: fix tx lost characters What is all of this below the patch for? Please clean up and send this properly, in a clean email, with no "Re:" on the subject line, as a new patch/email. thanks, greg k-h From mboxrd@z Thu Jan 1 00:00:00 1970 From: gregkh@linuxfoundation.org (gregkh at linuxfoundation.org) Date: Thu, 22 Mar 2018 18:35:29 +0100 Subject: [PATCH v3] serial: mvebu-uart: fix tx lost characters In-Reply-To: <3B588D51285A4A4D8D39C94212E07826279E39@SPQCMBX02.exfo.com> References: <3B588D51285A4A4D8D39C94212E07826279E39@SPQCMBX02.exfo.com> Message-ID: <20180322173529.GA24597@kroah.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Tue, Mar 20, 2018 at 04:09:38PM +0000, Gabriel Matni wrote: > From: Gabriel Matni > > Fixes missing characters on kernel console at low baud rates (i.e.9600). > The driver should poll TX_RDY or TX_FIFO_EMP instead of TX_EMP to ensure > that the transmitter holding register (THR) is ready to receive a new byte. > > TX_EMP tells us when it is possible to send a break sequence via > SND_BRK_SEQ. While this also indicates that both the THR and the TSR are > empty, it does not guarantee that a new byte can be written just yet. > > Fixes: 30530791a7a0 ("serial: mvebu-uart: initial support for Armada-3700 serial port") > Reviewed-by: Miquel Raynal > Acked-by: Gregory CLEMENT > Signed-off-by: Gabriel Matni > --- > Changes since v2: > - use one line for the "Fixes" entry > - removed trailing space between Signed-off-by entry and --- > - start using versioning, previous fixes in v1 > > Changes since v1: > - patch was corrupt, could not be applied > - fixed line indent > --- > drivers/tty/serial/mvebu-uart.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/tty/serial/mvebu-uart.c b/drivers/tty/serial/mvebu-uart.c > index a100e98259d7..f0df0640208e 100644 > --- a/drivers/tty/serial/mvebu-uart.c > +++ b/drivers/tty/serial/mvebu-uart.c > @@ -618,7 +618,7 @@ static void wait_for_xmitr(struct uart_port *port) > u32 val; > > readl_poll_timeout_atomic(port->membase + UART_STAT, val, > - (val & STAT_TX_EMP), 1, 10000); > + (val & STAT_TX_RDY(port)), 1, 10000); > } > > static void mvebu_uart_console_putchar(struct uart_port *port, int ch) > -- > 2.7.4 > > > > -----Original Message----- > > From: gregkh at linuxfoundation.org > > Sent: March 20, 2018 5:32 AM > > To: Gabriel Matni > > Cc: Miquel Raynal ; linux- > > serial at vger.kernel.org; linux-arm-kernel at lists.infradead.org; > > stable at vger.kernel.org; Gr?gory Clement ; > > Thomas Petazzoni > > Subject: Re: [PATCH] serial: mvebu-uart: fix tx lost characters What is all of this below the patch for? Please clean up and send this properly, in a clean email, with no "Re:" on the subject line, as a new patch/email. thanks, greg k-h From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:57800 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751670AbeCVRfe (ORCPT ); Thu, 22 Mar 2018 13:35:34 -0400 Date: Thu, 22 Mar 2018 18:35:29 +0100 From: "gregkh@linuxfoundation.org" To: Gabriel Matni Cc: Miquel Raynal , "linux-serial@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "stable@vger.kernel.org" , =?iso-8859-1?Q?Gr=E9gory?= Clement , Thomas Petazzoni Subject: Re: [PATCH v3] serial: mvebu-uart: fix tx lost characters Message-ID: <20180322173529.GA24597@kroah.com> References: <3B588D51285A4A4D8D39C94212E07826279E39@SPQCMBX02.exfo.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <3B588D51285A4A4D8D39C94212E07826279E39@SPQCMBX02.exfo.com> Sender: stable-owner@vger.kernel.org List-ID: On Tue, Mar 20, 2018 at 04:09:38PM +0000, Gabriel Matni wrote: > From: Gabriel Matni > > Fixes missing characters on kernel console at low baud rates (i.e.9600). > The driver should poll TX_RDY or TX_FIFO_EMP instead of TX_EMP to ensure > that the transmitter holding register (THR) is ready to receive a new byte. > > TX_EMP tells us when it is possible to send a break sequence via > SND_BRK_SEQ. While this also indicates that both the THR and the TSR are > empty, it does not guarantee that a new byte can be written just yet. > > Fixes: 30530791a7a0 ("serial: mvebu-uart: initial support for Armada-3700 serial port") > Reviewed-by: Miquel Raynal > Acked-by: Gregory CLEMENT > Signed-off-by: Gabriel Matni > --- > Changes since v2: > - use one line for the "Fixes" entry > - removed trailing space between Signed-off-by entry and --- > - start using versioning, previous fixes in v1 > > Changes since v1: > - patch was corrupt, could not be applied > - fixed line indent > --- > drivers/tty/serial/mvebu-uart.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/tty/serial/mvebu-uart.c b/drivers/tty/serial/mvebu-uart.c > index a100e98259d7..f0df0640208e 100644 > --- a/drivers/tty/serial/mvebu-uart.c > +++ b/drivers/tty/serial/mvebu-uart.c > @@ -618,7 +618,7 @@ static void wait_for_xmitr(struct uart_port *port) > u32 val; > > readl_poll_timeout_atomic(port->membase + UART_STAT, val, > - (val & STAT_TX_EMP), 1, 10000); > + (val & STAT_TX_RDY(port)), 1, 10000); > } > > static void mvebu_uart_console_putchar(struct uart_port *port, int ch) > -- > 2.7.4 > > > > -----Original Message----- > > From: gregkh@linuxfoundation.org > > Sent: March 20, 2018 5:32 AM > > To: Gabriel Matni > > Cc: Miquel Raynal ; linux- > > serial@vger.kernel.org; linux-arm-kernel@lists.infradead.org; > > stable@vger.kernel.org; Gr�gory Clement ; > > Thomas Petazzoni > > Subject: Re: [PATCH] serial: mvebu-uart: fix tx lost characters What is all of this below the patch for? Please clean up and send this properly, in a clean email, with no "Re:" on the subject line, as a new patch/email. thanks, greg k-h