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From: Richard Kennedy <richard@rsk.demon.co.uk>
To: Alan Stern <stern@rowland.harvard.edu>
Cc: dbrownell@users.sourceforge.net,
	linux-usb <linux-usb@vger.kernel.org>,
	lkml <linux-kernel@vger.kernel.org>
Subject: Re: ohci : strange looking use of round_jiffies_relative. possible bug ?
Date: Wed, 26 Mar 2008 15:46:45 +0000	[thread overview]
Message-ID: <1206546405.2931.20.camel@castor.localdomain> (raw)
In-Reply-To: <Pine.LNX.4.44L0.0803261136590.6324-100000@iolanthe.rowland.org>


On Wed, 2008-03-26 at 11:37 -0400, Alan Stern wrote:
> On Wed, 26 Mar 2008, Richard Kennedy wrote:
> 
> > I was looking at the uses of round_jiffies and noticed that the ohci
> > unlink_watchdog_func() calls 
> > mod_timer(&ohci->unlink_watchdog, round_jiffies_relative(HZ));
> > 
> > Which looks a bit strange as it will set the timer to 0 <= t < HZ.
> > Reading the comments I think that is really is expecting to setup timer
> > to (now + 1s)
> > 
> > mod_timer(&ohci->unlink_watchdog, round_jiffies(jiffies + HZ));
> > 
> > If this is not true then perhaps it needs a comment to explain what it
> > _is_ trying to do, because it's got me baffled ;)
> 
> I'd say it's a bug.  Or rather a pair of bugs, since that mod_timer() 
> call appears in two places.
> 
> Alan Stern
> 
Thanks. In that case I'll post a patch.
Richard 


  reply	other threads:[~2008-03-26 15:46 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-03-26 14:38 Richard Kennedy
2008-03-26 15:37 ` Alan Stern
2008-03-26 15:46   ` Richard Kennedy [this message]
2008-03-26 18:06     ` Mike Nuss
2008-03-27 18:55       ` David Brownell
2008-03-26 16:32   ` [patch] usb ohci : fix 2 timers to fire at jiffies + 1s Richard Kennedy
2008-03-27 18:53     ` David Brownell

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