From: Greg KH <gregkh@linuxfoundation.org>
To: Fabio Estevam <festevam@gmail.com>
Cc: Paul Geurts <paul_geurts@live.nl>,
jirislaby@kernel.org, shawnguo@kernel.org,
s.hauer@pengutronix.de, kernel@pengutronix.de, linux-imx@nxp.com,
u.kleine-koenig@pengutronix.de, linux-kernel@vger.kernel.org,
linux-serial@vger.kernel.org,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v2] serial: imx: fix tx statemachine deadlock
Date: Fri, 24 Nov 2023 13:03:25 +0000 [thread overview]
Message-ID: <2023112434-winter-embezzle-1b46@gregkh> (raw)
In-Reply-To: <CAOMZO5AgDjwUeePO4ibUeKkpf-YV9v=Dws0S01HMERdDf85yoQ@mail.gmail.com>
On Fri, Nov 24, 2023 at 09:58:19AM -0300, Fabio Estevam wrote:
> Hi Paul,
>
> On Fri, Nov 24, 2023 at 9:55 AM Paul Geurts <paul_geurts@live.nl> wrote:
> >
> > When using the serial port as RS485 port, the tx statemachine is used to
> > control the RTS pin to drive the RS485 transceiver TX_EN pin. When the
> > TTY port is closed in the middle of a transmission (for instance during
> > userland application crash), imx_uart_shutdown disables the interface
> > and disables the Transmission Complete interrupt. afer that,
> > imx_uart_stop_tx bails on an incomplete transmission, to be retriggered
> > by the TC interrupt. This interrupt is disabled and therefore the tx
> > statemachine never transitions out of SEND. The statemachine is in
> > deadlock now, and the TX_EN remains low, making the interface useless.
> >
> > imx_uart_stop_tx now checks for incomplete transmission AND whether TC
> > interrupts are enabled before bailing to be retriggered. This makes sure
> > the state machine handling is reached, and is properly set to
> > WAIT_AFTER_SEND.
> >
> > Fixes: cb1a60923609 serial: imx: implement rts delaying for rs485
>
> One nit: the correct format for the Fixes tag is:
>
> Fixes: cb1a60923609 ("serial: imx: implement rts delaying for rs485")
>
> And no blank line is needed between the Fixes and Signed-off-by line.
It's not really a "nit", our tools will complain if this is in the wrong
format as so many things depend on this being correct.
Paul, can you make a v3 with this change?
And really, this should have been v3 anyway, as the difference being you
added a changelog from v2 :)
thanks,
greg k-h
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next prev parent reply other threads:[~2023-11-24 13:04 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-04 9:57 [PATCH] serial: imx: fix tx statemachine deadlock Paul Geurts
2023-10-04 10:20 ` Uwe Kleine-König
2023-10-05 8:51 ` Paul Geurts
2023-10-04 12:13 ` Greg KH
2023-11-24 12:38 ` [PATCH v2] " Paul Geurts
2023-11-24 12:45 ` Greg KH
2023-11-24 12:53 ` Paul Geurts
2023-11-24 12:58 ` Fabio Estevam
2023-11-24 13:03 ` Greg KH [this message]
2023-11-24 13:11 ` [PATCH v3] " Paul Geurts
2023-11-24 13:37 ` Rasmus Villemoes
2023-11-24 13:55 ` Paul Geurts
2023-11-30 9:09 ` Rasmus Villemoes
2023-12-01 16:55 ` Eberhard Stoll
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