From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTP id D62F7DDE3C for ; Fri, 18 May 2007 15:05:40 +1000 (EST) Subject: Re: [PATCH 2.6.21-rt2] PowerPC: decrementer clockevent driver From: Benjamin Herrenschmidt To: Segher Boessenkool In-Reply-To: <97d47c2261fe9cd3f1a6c864278a6ab6@kernel.crashing.org> References: <200705172142.26739.sshtylyov@ru.mvista.com> <464CB071.5050504@ru.mvista.com> <9095839480a9686d9c40aa6143edb804@kernel.crashing.org> <464CB460.40905@ru.mvista.com> <97d47c2261fe9cd3f1a6c864278a6ab6@kernel.crashing.org> Content-Type: text/plain Date: Fri, 18 May 2007 15:04:49 +1000 Message-Id: <1179464690.32247.370.camel@localhost.localdomain> Mime-Version: 1.0 Cc: linuxppc-dev@ozlabs.org, tglx@linutronix.de, mingo@elte.hu, linux-kernel@vger.kernel.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , > > Yes, on some implementations there can be other conditions that > make a decrementer exception go away; there is no contradiction > here (thankfully). My wording was sloppy. Some CPUs have the DEC exceptions basically edge triggered (yeah I know it sucks). That's why, among others, the IRQ soft-disable code has code to re-trigger DEC exceptions ASAP (by setting it to 1.. note that we could probably use 0 here, we've been a bit conservative). Ben.