Re: 3c59x vortex_timer rt hack (was: rt20 patch question)

[Steven Rostedt <rostedt@goodmis.org>]

On Fri, 12 May 2006, Andrew Morton wrote:

>
> So yes, doing spin_lock_irq() (irqrestore isn't needed in a timer handler)
> instead of disable_irq() in vortex_timer() looks OK.
>
> One does wonder how long we'll hold off interrupts though.

Any longer than this!

in boomerang_start_xmit()

	spin_lock_irqsave(&vp->lock, flags);

	/* Wait for the stall to complete. */
	issue_and_wait(dev, DownStall);

  Pretty big wait!

    [...]

	spin_unlock_irqrestore(&vp->lock, flags);


Where we have in issue_and_wait

static void
issue_and_wait(struct net_device *dev, int cmd)
{

 [...]

	/* OK, that didn't work.  Do it the slow way.  One second */
	for (i = 0; i < 100000; i++) {

 [...]
}

So this can have interrupts off for over a second!

-- Steve

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