lkml.org 
[lkml]   [2011]   [Aug]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
SubjectRe: Possible bug in 8250.c
From
I traced the function using jtag debugger. 

UART is not sharing interrupts:
========================================= Console ========================
Serial: 8250/16550 driver, 1 ports, IRQ sharing disabled
serial8250.0: ttyS0 at MMIO 0xae023400 (irq = 53) is a 16550A
console [ttyS0] enabled, bootconsole disabled
=========================================================================
And /proc/interrupts:

=========================================================================
cat /proc/interrupts
CPU0
53: 4534 XXXXX serial
56: 12 XXXXX phy_interrupt
153: 20262068 XXXXX timer
ERR: 0
=========================================================================

So in first iteration, interrupt is cleared, and in second, function will execute:

} else if (end == NULL)
end = l;

which will terminate the loop, but the return code will be IRQ_RETVAL(0).




On Fri 19/08/11 12:01 , Jiri Slaby <jslaby@suse.cz> wrote:

> 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
>
>
>


\
 
 \ /
  Last update: 2011-08-20 03:01    [W:0.055 / U:0.096 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site