Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934140AbXEVLX0 (ORCPT ); Tue, 22 May 2007 07:23:26 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755107AbXEVLXT (ORCPT ); Tue, 22 May 2007 07:23:19 -0400 Received: from brick.kernel.dk ([80.160.20.94]:1994 "EHLO kernel.dk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754375AbXEVLXS (ORCPT ); Tue, 22 May 2007 07:23:18 -0400 Date: Tue, 22 May 2007 13:20:49 +0200 From: Jens Axboe To: Ingo Molnar Cc: Jeff Garzik , Thomas Gleixner , LKML , Alan Cox Subject: Re: [PATCH] CDROM: replace jiffies busyloop with msleep Message-ID: <20070522112047.GS4705@kernel.dk> References: <1179829525.12708.118.camel@chaos> <4652C640.3090806@garzik.org> <20070522112140.GB16308@elte.hu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070522112140.GB16308@elte.hu> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1400 Lines: 39 On Tue, May 22 2007, Ingo Molnar wrote: > > * Jeff Garzik wrote: > > > >@@ -1709,12 +1710,11 @@ static int __init sjcd_init(void) > > > printk(KERN_INFO "SJCD: Resetting: "); > > > sjcd_send_cmd(SCMD_RESET); > > > for (i = 1000; i > 0 && !sjcd_status_valid; --i) { > > >- unsigned long timer; > > >- > > > /* > > > * Wait 10ms approx. > > > */ > > >- for (timer = jiffies; time_before_eq(jiffies, timer);); > > >+ msleep(10); > > >+ > > > > I always worry when I see code like this, wondering if there is some > > arcane reason that I cannot fathom, that is being removed. You gotta > > wonder how long it has been since this driver was used, by anybody. > > > > Oh well, I cannot find fault with the patch, paranoia worries aside. > > well, while i dont have that hardware, i found this by booting an > allyesconfig bzImage which runs the code above, which locks up without > this change. And then it booted fine with this change. So arcane issues > aside, it does visibly improve things ;-) But if you looked at the driver, you'd see 2 other identical busy loops in the very same function :-) -- Jens Axboe - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/