linux-kernel - Re: Possible bug in 8250.c

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Message-ID: <4E4EB31B.70709@suse.cz>
Date:	Fri, 19 Aug 2011 21:01:47 +0200
From:	Jiri Slaby <jslaby@...e.cz>
To:	mikeci@....org
CC:	linux-kernel@...r.kernel.org
Subject: Re: Possible bug in 8250.c

On 08/19/2011 07:44 PM, Ivica Mikec wrote:
> 
>  Hi!
> 
> 
> I noticed a problem in 8250.c. 
> 
> My board has only one UART port, and is 16550 compatible, so in function serial8250_interrupt I see that serial_in function is called twice. Second time, code "else if (end == NULL)" is executed and function return IRQ_NONE. This causes an entry in /proc/irq/spurious:
> 
> count 239
> unhandled 1
> last_unhandled 4294700846 ms
> 
> But this is not a spurious interrupt.

How did you find out? Have you checked that the port signals that it
raised an interrupt? I.e. does it go through the 'if (!(iir &
UART_IIR_NO_INT))' branch?

What other devices are bound to the same interrupt? Attach /proc/interrupts.

regards,
-- 
js
suse labs
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