From: "Kim, Jong-Sung" <neidhard.kim@lge.com>
To: 'Russell King - ARM Linux' <linux@arm.linux.org.uk>,
'Linus Walleij' <linus.walleij@stericsson.com>
Cc: 'Greg Kroah-Hartman' <gregkh@suse.de>,
linux-serial@vger.kernel.org, 'Chanho Min' <chanho0207@gmail.com>,
linux-arm-kernel@lists.infradead.org,
'Linus Walleij' <linus.walleij@linaro.org>,
stable@kernel.org,
'Shreshtha Kumar Sahu' <shreshthakumar.sahu@stericsson.com>
Subject: RE: [PATCH] serial: PL011: clear pending interrupts
Date: Mon, 12 Mar 2012 20:22:07 +0900 [thread overview]
Message-ID: <01e101cd0042$5bf692a0$13e3b7e0$@lge.com> (raw)
In-Reply-To: <20120312083221.GW17370@n2100.arm.linux.org.uk>
> > diff --git a/drivers/tty/serial/amba-pl011.c
> > b/drivers/tty/serial/amba-pl011.c index 6800f5f..ff3fed0 100644
> > --- a/drivers/tty/serial/amba-pl011.c
> > +++ b/drivers/tty/serial/amba-pl011.c
> > @@ -224,6 +224,11 @@ static int pl011_fifo_to_tty(struct uart_amba_port
> *uap)
> > uart_insert_char(&uap->port, ch, UART011_DR_OE, ch, flag);
> > }
> >
>
> What if we really do end up receiving some characters here?
Maybe the character is handled on next upcoming RTIS or RXIS in normal.
However, I agree with you there is possibility of already asserted RXIS at
this point. (with debugger?) In such a case, we may lose Rx interrupts
forever because it's not level-triggered, and the ISR lacks error interrupt
handling. Correct me if something wrong.
Thank you for your comment, Russell.
>
> > + /* RXIS but RXFE? Just clear the interrupt */
> > + if(unlikely(fifotaken == 0))
> > + writew(UART011_RTIS | UART011_RXIS,
> > + uap->port.membase + UART011_ICR);
WARNING: multiple messages have this Message-ID (diff)
From: neidhard.kim@lge.com (Kim, Jong-Sung)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] serial: PL011: clear pending interrupts
Date: Mon, 12 Mar 2012 20:22:07 +0900 [thread overview]
Message-ID: <01e101cd0042$5bf692a0$13e3b7e0$@lge.com> (raw)
In-Reply-To: <20120312083221.GW17370@n2100.arm.linux.org.uk>
> > diff --git a/drivers/tty/serial/amba-pl011.c
> > b/drivers/tty/serial/amba-pl011.c index 6800f5f..ff3fed0 100644
> > --- a/drivers/tty/serial/amba-pl011.c
> > +++ b/drivers/tty/serial/amba-pl011.c
> > @@ -224,6 +224,11 @@ static int pl011_fifo_to_tty(struct uart_amba_port
> *uap)
> > uart_insert_char(&uap->port, ch, UART011_DR_OE, ch, flag);
> > }
> >
>
> What if we really do end up receiving some characters here?
Maybe the character is handled on next upcoming RTIS or RXIS in normal.
However, I agree with you there is possibility of already asserted RXIS at
this point. (with debugger?) In such a case, we may lose Rx interrupts
forever because it's not level-triggered, and the ISR lacks error interrupt
handling. Correct me if something wrong.
Thank you for your comment, Russell.
>
> > + /* RXIS but RXFE? Just clear the interrupt */
> > + if(unlikely(fifotaken == 0))
> > + writew(UART011_RTIS | UART011_RXIS,
> > + uap->port.membase + UART011_ICR);
next prev parent reply other threads:[~2012-03-12 11:22 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-12 8:25 [PATCH] serial: PL011: clear pending interrupts Linus Walleij
2012-03-12 8:25 ` Linus Walleij
2012-03-12 8:32 ` Russell King - ARM Linux
2012-03-12 8:32 ` Russell King - ARM Linux
2012-03-12 10:11 ` Russell King - ARM Linux
2012-03-12 10:11 ` Russell King - ARM Linux
2012-03-12 10:48 ` Linus Walleij
2012-03-12 10:48 ` Linus Walleij
2012-03-12 11:28 ` Kim, Jong-Sung
2012-03-12 11:28 ` Kim, Jong-Sung
2012-03-12 11:22 ` Kim, Jong-Sung [this message]
2012-03-12 11:22 ` Kim, Jong-Sung
2012-03-12 11:28 ` Russell King - ARM Linux
2012-03-12 11:28 ` Russell King - ARM Linux
2012-03-12 9:27 ` James Courtier-Dutton
2012-03-12 9:27 ` James Courtier-Dutton
2012-03-12 10:03 ` Russell King - ARM Linux
2012-03-12 10:03 ` Russell King - ARM Linux
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