From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ben Collins Subject: Re: [PATCH] Cleanup libata HPA support Date: Tue, 08 May 2007 16:43:14 +0200 Message-ID: <1178635394.6962.97.camel@cunning> References: <1178621978.6962.75.camel@cunning> <46407ED4.9090301@rtr.ca> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Return-path: Received: from adelie.ubuntu.com ([82.211.81.139]:42331 "EHLO adelie.ubuntu.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S968285AbXEHOnU (ORCPT ); Tue, 8 May 2007 10:43:20 -0400 In-Reply-To: <46407ED4.9090301@rtr.ca> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Mark Lord Cc: linux-kernel@vger.kernel.org, alan@lxorguk.ukuu.org.uk, Kyle McMartin , linux-ide@vger.kernel.org On Tue, 2007-05-08 at 09:44 -0400, Mark Lord wrote: > Ben Collins wrote: > .. > > static u64 ata_tf_to_lba48(struct ata_taskfile *tf) > > { > > - u64 sectors = 0; > > + u64 sectors; > > + u32 high, low; > > > > - sectors |= ((u64)(tf->hob_lbah & 0xff)) << 40; > > - sectors |= ((u64)(tf->hob_lbam & 0xff)) << 32; > > - sectors |= (tf->hob_lbal & 0xff) << 24; > > - sectors |= (tf->lbah & 0xff) << 16; > > - sectors |= (tf->lbam & 0xff) << 8; > > - sectors |= (tf->lbal & 0xff); > > + high = (tf->hob_lbah << 16) | > > + (tf->hob_lbam << 8) | > > + tf->hob_lbal; > > + low = (tf->lbah << 16) | > > + (tf->lbam << 8) | > > + tf->lbal; > > > > - return ++sectors; > > + sectors = ((u64)high << 24) | low; > > + > > + return sectors + 1; > > } > > Ben, I very much prefer the fixed version of this function > as implemented by the patch above. > > But.. is the original code actually broken, or just messy? Due to the bugs we were seeing, we actually noticed that this function was having signed extension issues as originally implemented. I didn't look for the actual bug, but reimplemented it based on code in ide_disk.c, which resolved the issue. -- Ubuntu : http://www.ubuntu.com/ Linux1394: http://wiki.linux1394.org/