From mboxrd@z Thu Jan 1 00:00:00 1970 From: khali@linux-fr.org (Jean Delvare) Date: Thu, 19 May 2005 06:25:35 +0000 Subject: [PATCH 2.6] I2C: New chip driver: sis5595 Message-Id: List-Id: In-Reply-To: References: <20050125220945.GA23560@bode.aurel32.net> In-Reply-To: <20050125220945.GA23560@bode.aurel32.net> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: adobriyan@mail.ru Cc: Aurelien Jarno , Greg KH , LKML , LM Sensors Quoting myself: > To me, the only acceptable simplification is > the initialization of "last_updated" to something which ensures that > the first update attempt will succeed - providing we actually can do > that. On second thought, we obviously cannot, because jiffies wrap, so there is no single initial value of "last_updated", either relative or absolute, which can ensure this condition to be true. I think we are stuck we this "valid" flag, or at least with the concept thereof. Possibly we can use "last_updated" itself as a flag if we absolutely want to get rid of "valid". "last_updated = 0" would mean the same as "valid = 0" did. The probability of "last_updated" to become 0 again after init time is obviously thin, and it wouldn't really hurt if it did (it would simply allow an extra update to happen). That said, this makes the code somewhat trickier. What could (and should) be done anyway is to use time_after() or something equivalent for the jiffies checks, instead of direct coparison, in all hardware monitoring drivers. Thanks, -- Jean Delvare From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262029AbVBAOuN (ORCPT ); Tue, 1 Feb 2005 09:50:13 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262030AbVBAOuN (ORCPT ); Tue, 1 Feb 2005 09:50:13 -0500 Received: from zone4.gcu-squad.org ([213.91.10.50]:64724 "EHLO zone4.gcu-squad.org") by vger.kernel.org with ESMTP id S262029AbVBAOuA convert rfc822-to-8bit (ORCPT ); Tue, 1 Feb 2005 09:50:00 -0500 Date: Tue, 1 Feb 2005 15:43:24 +0100 (CET) To: adobriyan@mail.ru Subject: Re: [PATCH 2.6] I2C: New chip driver: sis5595 X-IlohaMail-Blah: khali@localhost X-IlohaMail-Method: mail() [mem] X-IlohaMail-Dummy: moo X-Mailer: IlohaMail/0.8.13 (On: webmail.gcu.info) Message-ID: In-Reply-To: From: "Jean Delvare" Bounce-To: "Jean Delvare" CC: "Aurelien Jarno" , "Greg KH" , "LKML" , "LM Sensors" MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Quoting myself: > To me, the only acceptable simplification is > the initialization of "last_updated" to something which ensures that > the first update attempt will succeed - providing we actually can do > that. On second thought, we obviously cannot, because jiffies wrap, so there is no single initial value of "last_updated", either relative or absolute, which can ensure this condition to be true. I think we are stuck we this "valid" flag, or at least with the concept thereof. Possibly we can use "last_updated" itself as a flag if we absolutely want to get rid of "valid". "last_updated == 0" would mean the same as "valid == 0" did. The probability of "last_updated" to become 0 again after init time is obviously thin, and it wouldn't really hurt if it did (it would simply allow an extra update to happen). That said, this makes the code somewhat trickier. What could (and should) be done anyway is to use time_after() or something equivalent for the jiffies checks, instead of direct coparison, in all hardware monitoring drivers. Thanks, -- Jean Delvare