From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matthew Wilcox Subject: Re: [PATCH] Stall semantics Date: Wed, 1 Oct 2003 19:55:24 +0100 Sender: acpi-devel-admin-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Message-ID: <20031001185524.GX24824@parcelfarce.linux.theplanet.co.uk> References: <20031001093943.J85056@root.org> <20031001171657.GW24824@parcelfarce.linux.theplanet.co.uk> <20031001101854.J85056@root.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20031001101854.J85056-Y6VGUYTwhu0@public.gmane.org> Errors-To: acpi-devel-admin-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Help: List-Post: List-Subscribe: , List-Unsubscribe: , List-Archive: To: Nate Lawson Cc: Matthew Wilcox , "Moore, Robert" , acpi-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: linux-acpi@vger.kernel.org On Wed, Oct 01, 2003 at 10:27:04AM -0700, Nate Lawson wrote: > You're assuming the AML mistake is made both ways. If it is uniformly > made one way, it's easy to work around correctly. Actually, I assume that AML writers are idiots who can't read the spec. They almost certainly want to stall for 2 seconds. The fact that they can't doesn't stop them trying. > > I think the current ACPI behaviour is probably adequate -- accommodate > > incopetent BIOS writers up to a point, then sleep, and damn them anyway. > > It damns us OS vendors a different way in that we get unacceptably long > idle spin loops on some machines. Spinning for 1000 us is not correct any > way you interpret the standard. You have a machine which isn't able to stall for 1 millisecond? Many drivers do stall for that much, and more. Grepping the linux-2.6 tree shows a lot of drivers calling mdelay() -- tulip, e1000, symbios, aic7xxx, radeon, mach64, ohci, uhci, ide, ... One gem.. ./drivers/ide/pci/pdc202xx_new.c: mdelay(2000); /* 2 seconds ?! */ I don't think a 1ms stall is exceptional, or even remarkable. -- "It's not Hollywood. War is real, war is primarily not about defeat or victory, it is about death. I've seen thousands and thousands of dead bodies. Do you think I want to have an academic debate on this subject?" -- Robert Fisk ------------------------------------------------------- This sf.net email is sponsored by:ThinkGeek Welcome to geek heaven. http://thinkgeek.com/sf