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Date: Sat, 28 Sep 2002 09:06:17 +0100
From: Russell King <rmk@arm.linux.org.uk>
To: Dave Hansen <haveblue@us.ibm.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: sysrq on serial console
Message-ID: <20020928090617.A32639@flint.arm.linux.org.uk>
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In-Reply-To: <3D94ED88.5040407@us.ibm.com>; from haveblue@us.ibm.com on Fri, Sep 27, 2002 at 04:45:12PM -0700
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On Fri, Sep 27, 2002 at 04:45:12PM -0700, Dave Hansen wrote:
> It looks like the UART_LSR_BI bit needs to be set in the status 
> variable for the break character to be interpreted as a break in the 
> driver.

That is correct; that is how the UART reports a break character.

> I doubt that it is actually broken,  but it isn't immediately obvious 
> how that bit gets set.  Is there something that I should have set when 
> the device was initialized to make sure that UART_LSR_BI is asserted 
> in "status" when the interrupt occurs?

Now.  Its a status bit from the UART LSR register itself, read from
serial8250_handle_port() and receive_chars().  It will cause an
interrupt any time that the receive interrupt is enabled, ie when
the port is open by user space.

-- 
Russell King (rmk@arm.linux.org.uk)                The developer of ARM Linux
             http://www.arm.linux.org.uk/personal/aboutme.html

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