Re: tickle nmi watchdog whilst doing serial writes.

[Bill Davidsen <davidsen@tmr.com>]

Russell King wrote:
> On Wed, May 18, 2005 at 05:24:13PM -0700, George Anzinger wrote:
> 
>>Um... I would think the real fix is to set the UART up to generate the modem 
>>status interrupt and eliminate the pole loop.  Why can't this be done?  I, for 
>>one, don't want my cpu looping in the serial driver, even more so with the 
>>interrupt system off.  This, in my mind, is a real bug in the serial driver and 
>>should be so handled.
> 
> 
> Because printk is *synchronous*.  It never returns until it's written
> the entire message.  There is no buffering.
> 
> Extra complexity, adding reliance on interrupts, etc all means that
> you reduce the probability that you'll get the panic or oops message
> out of the system.
> 
This is a fine reason to loop in the serial code, I guess, but what's 
the reason for allowing the NMI oops? Having use of the serial console 
to catch an oops actually CAUSE an oops doesn't seem desirable, and is 
probably more likely than a hardlock in the serial driver.

-- 
    -bill davidsen (davidsen@tmr.com)
"The secret to procrastination is to put things off until the
  last possible moment - but no longer"  -me