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Re: UART trouble on the DBAu1100

To: Domen Puncer <domen.puncer@ultra.si>
Subject: Re: UART trouble on the DBAu1100
From: Jon Anders Haugum <jonah@omegav.ntnu.no>
Date: Thu, 20 Apr 2006 15:11:34 +0200 (CEST)
Cc: Freddy Spierenburg <freddy@dusktilldawn.nl>, linux-mips@linux-mips.org
In-reply-to: <20060414060640.GE29489@domen.ultra.si>
Original-recipient: rfc822;linux-mips@linux-mips.org
References: <20060413131117.GP11097@dusktilldawn.nl> <20060414060640.GE29489@domen.ultra.si>
Sender: linux-mips-bounce@linux-mips.org
On Fri, 14 Apr 2006, Domen Puncer wrote:

> On 13/04/06 15:11 +0200, Freddy Spierenburg wrote:
> 
> > But that's not the only trouble. I also do not receive any
> > bytes received by the UART. All the received bytes stay
> > in the input buffer of the UART only to be send up to userland
> > as soon as the UART is asked to send a byte on the line itself.
> > Then in one take all the bytes are received by the application
> > listening.
> 
> I may be way off, but maybe it's just flow control that needs
> to be turned off.

If this is uart 0, it's probably a problem with that uart having irq 
number 0. Which in the 8250 driver is interpreted as no interrupt.

A quick (and dirty) patch:

--- linux/drivers/serial/8250.c_org     2006-03-31 16:07:57.682822888 +0200
+++ linux/drivers/serial/8250.c 2006-03-31 16:08:22.969978656 +0200
@@ -78,7 +78,7 @@ static unsigned int nr_uarts = CONFIG_SE
  * machine types want others as well - they're free
  * to redefine this in their header file.
  */
-#define is_real_interrupt(irq) ((irq) != 0)
+#define is_real_interrupt(irq) (1)
 
 #ifdef CONFIG_SERIAL_8250_DETECT_IRQ
 #define CONFIG_SERIAL_DETECT_IRQ 1



But this is not a desired solution according to this: 
http://lkml.org/lkml/2006/3/29/91

Have somebody got a idea about how a mapping of interrupt numbers should 
be done in order to avoid irq 0 for Alchemy?


-- 
Jon Anders Haugum


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