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
Date: Sat, 28 Sep 2002 09:06:17 +0100 [thread overview]
Message-ID: <20020928090617.A32639@flint.arm.linux.org.uk> (raw)
In-Reply-To: <3D94ED88.5040407@us.ibm.com>; from haveblue@us.ibm.com on Fri, Sep 27, 2002 at 04:45:12PM -0700
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
prev parent reply other threads:[~2002-09-28 8:00 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-09-27 23:45 sysrq on serial console Dave Hansen
2002-09-28 0:29 ` H. Peter Anvin
2002-09-28 8:06 ` Russell King [this message]
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