Linux Serial subsystem development
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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);


  parent reply	other threads:[~2012-03-12 11:22 UTC|newest]

Thread overview: 9+ 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  8:32 ` Russell King - ARM Linux
2012-03-12 10:11   ` Russell King - ARM Linux
2012-03-12 10:48     ` Linus Walleij
2012-03-12 11:28     ` Kim, Jong-Sung
2012-03-12 11:22   ` Kim, Jong-Sung [this message]
2012-03-12 11:28     ` Russell King - ARM Linux
2012-03-12  9:27 ` James Courtier-Dutton
2012-03-12 10:03   ` Russell King - ARM Linux

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