From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761146AbXEYM06 (ORCPT ); Fri, 25 May 2007 08:26:58 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1759928AbXEYM0s (ORCPT ); Fri, 25 May 2007 08:26:48 -0400 Received: from srv5.dvmed.net ([207.36.208.214]:54321 "EHLO mail.dvmed.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759830AbXEYM0r (ORCPT ); Fri, 25 May 2007 08:26:47 -0400 Message-ID: <4656D602.3010105@garzik.org> Date: Fri, 25 May 2007 08:26:42 -0400 From: Jeff Garzik User-Agent: Thunderbird 1.5.0.10 (X11/20070302) MIME-Version: 1.0 To: Tejun Heo CC: Alan Cox , linux-ide@vger.kernel.org, Linux Kernel Mailing List Subject: Re: [PATCH] libata: always use polling SETXFER References: <20070314053338.GA15600@htj.dyndns.org> <4656C144.2080705@garzik.org> <4656CF83.5020402@gmail.com> In-Reply-To: <4656CF83.5020402@gmail.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Score: -4.3 (----) X-Spam-Report: SpamAssassin version 3.1.8 on srv5.dvmed.net summary: Content analysis details: (-4.3 points, 5.0 required) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Tejun Heo wrote: > So, I don't think the problem exists for SATA in the first place. At > least there hasn't been any report of it and doing SETXFER by polling > can handle all the existing cases. We can and probably should deal with > such SATA devices when and if they come up. How are we gonna verify the > controller doesn't crap itself and ahci TF register monitoring HSM can > work around the weirdo when we don't have any such device? Even if we > determine that we need to do HSM over intelligent SATA controller now, I > think we still need to push polling SETXFER first to take care of the > existing cases. Doing SETXFER by polling only handles the cases where the driver actually honors ATA_TFLAG_POLLING, which is /not/ always the case. If the new policy ensures that it continues to be OK to /not/ honor ATA_TFLAG_POLLING -- thus limiting SETXFER polling assumptions to older hardware -- that's fine, and it merely needs to be documented. But let us not make the assumption that this bandaid fixes all cases, because the bandaid is not applied in all cases. Jeff