Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263205AbUCTCxT (ORCPT ); Fri, 19 Mar 2004 21:53:19 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263207AbUCTCxT (ORCPT ); Fri, 19 Mar 2004 21:53:19 -0500 Received: from mail.convergence.de ([212.84.236.4]:20950 "EHLO mail.convergence.de") by vger.kernel.org with ESMTP id S263205AbUCTCxR (ORCPT ); Fri, 19 Mar 2004 21:53:17 -0500 Date: Sat, 20 Mar 2004 03:53:12 +0100 From: Johannes Stezenbach To: Bartlomiej Zolnierkiewicz Cc: Matthias Andree , Linux Kernel Subject: Re: [PATCH] barrier patch set Message-ID: <20040320025312.GA12710@convergence.de> Mail-Followup-To: Johannes Stezenbach , Bartlomiej Zolnierkiewicz , Matthias Andree , Linux Kernel References: <20040319153554.GC2933@suse.de> <200403200102.39716.bzolnier@elka.pw.edu.pl> <20040320014837.GB11865@convergence.de> <200403200313.05681.bzolnier@elka.pw.edu.pl> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200403200313.05681.bzolnier@elka.pw.edu.pl> User-Agent: Mutt/1.5.5.1+cvs20040105i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1141 Lines: 30 Bartlomiej Zolnierkiewicz wrote: > On Saturday 20 of March 2004 02:48, Johannes Stezenbach wrote: > > > hdparm -i and -I ultimately both interpret WIN_IDENTIFY result, and both > > test bit 0x0020 of word 85. So it's unclear to me why they report a > > different write cache setting. I added a hexdump to dump_identity() > > in hdparm.c, and found that bit 0x0020 of word 85 is always set. > > or WIN_PIDENTIFY to be strict but > > -i returns _cached_ (read when the device was probed) identify data > (uses HDIO_GET_IDENTIFY ioctl) > -I reads _current_ data directly from the device > (uses HDIO_DRIVE_CMD ioctl) Oh, right. But: HDIO_GET_IDENTITY returns drive->id, and surely drive->id is used internally. So isn't it a bug that drive->id is not updated when the write cache setting is changed? I think the barrier code uses drive->id to determine if the write cache is enabled. Johannes - 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/