Re: tickle nmi watchdog whilst doing serial writes.

[Russell King <rmk+lkml@arm.linux.org.uk>]

On Sun, May 15, 2005 at 01:38:02PM +0200, Andi Kleen wrote:
> Dave Jones <davej@redhat.com> writes:
> >  
> >  #include <asm/io.h>
> >  #include <asm/irq.h>
> > @@ -2099,8 +2100,10 @@ static inline void wait_for_xmitr(struct
> >  	if (up->port.flags & UPF_CONS_FLOW) {
> >  		tmout = 1000000;
> >  		while (--tmout &&
> > -		       ((serial_in(up, UART_MSR) & UART_MSR_CTS) == 0))
> > +		       ((serial_in(up, UART_MSR) & UART_MSR_CTS) == 0)) {
> >  			udelay(1);
> > +			touch_nmi_watchdog();
> 
> Note that touch_nmi_watchdog is not exported on i386 - Linus vetoed
> that some time ago. The real fix of course is to use schedule_timeout(),
> but that might break printk() with interrupts off :/

Not to mention printk() from atomic contexts and panic().  No,
schedule_timeout() is _not_ a "real fix" but a kludge.

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