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From: Russell King <rmk+lkml@arm.linux.org.uk>
To: Petr Vandrovec <vandrove@vc.cvut.cz>, Chris Wedgwood <cw@f00f.org>
Cc: linux-kernel@vger.kernel.org
Subject: Re: XScale 8250 patches cause malfunction on AMD-8111
Date: Mon, 7 Mar 2005 21:31:48 +0000	[thread overview]
Message-ID: <20050307213148.B29948@flint.arm.linux.org.uk> (raw)
In-Reply-To: <20050307195654.GA9394@vana.vc.cvut.cz>; from vandrove@vc.cvut.cz on Mon, Mar 07, 2005 at 08:56:54PM +0100

On Mon, Mar 07, 2005 at 08:56:54PM +0100, Petr Vandrovec wrote:
> Well, problem is not in bit 6 in IER, but in bit 6 in high divisor byte,
> as DLAB is set to one from previous probe.  This simple clear of LCR
> register fixes problem with (probably all 16550A) chips being detected
> as XScale, and in addition to it it does not switch my 115200Bd serial
> line to 7Bd mode (0x4001 divisor) anymore.

Good catch, thanks.  I'd preferably like to see Chris Wedgwood test this
before applying it - I'm sure it'll fix his problem as well, but I'd
like to be sure.

--- linux-2.6.11-c1994.dist/drivers/serial/8250.c	2005-03-07 17:22:21.000000000 +0100
+++ linux-2.6.11-c1994/drivers/serial/8250.c	2005-03-07 20:42:53.000000000 +0100
@@ -729,6 +729,7 @@
 	serial_outp(up, UART_FCR, UART_FCR_ENABLE_FIFO | UART_FCR7_64BYTE);
 	status2 = serial_in(up, UART_IIR) >> 5;
 	serial_outp(up, UART_FCR, UART_FCR_ENABLE_FIFO);
+	serial_outp(up, UART_LCR, 0);
 
 	DEBUG_AUTOCONF("iir1=%d iir2=%d ", status1, status2);
 

-- 
Russell King
 Linux kernel    2.6 ARM Linux   - http://www.arm.linux.org.uk/
 maintainer of:  2.6 Serial core

  reply	other threads:[~2005-03-07 21:49 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-03-07 17:45 XScale 8250 patches cause malfunction on AMD-8111 Petr Vandrovec
2005-03-07 19:56 ` Petr Vandrovec
2005-03-07 21:31   ` Russell King [this message]
2005-03-08  2:16     ` Andrew Morton
2005-03-10 21:05     ` Chris Wedgwood
2005-03-10 21:21       ` Russell King

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