From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Garzik Subject: Re: [PATCH] libata: always use polling SETXFER Date: Fri, 25 May 2007 08:26:42 -0400 Message-ID: <4656D602.3010105@garzik.org> References: <20070314053338.GA15600@htj.dyndns.org> <4656C144.2080705@garzik.org> <4656CF83.5020402@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: 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 In-Reply-To: <4656CF83.5020402@gmail.com> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Tejun Heo Cc: Alan Cox , linux-ide@vger.kernel.org, Linux Kernel Mailing List 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