From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: Re: [PATCH 4/4] libata: implement ATAPI per-command-type DMA horkages Date: Wed, 02 Jan 2008 22:49:29 +0900 Message-ID: <477B9669.1060602@gmail.com> References: <11992723701811-git-send-email-htejun@gmail.com> <1199272371169-git-send-email-htejun@gmail.com> <20080102133445.338b4296@the-village.bc.nu> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from rv-out-0910.google.com ([209.85.198.186]:8675 "EHLO rv-out-0910.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751146AbYABNtg (ORCPT ); Wed, 2 Jan 2008 08:49:36 -0500 Received: by rv-out-0910.google.com with SMTP id k20so5278102rvb.1 for ; Wed, 02 Jan 2008 05:49:34 -0800 (PST) In-Reply-To: <20080102133445.338b4296@the-village.bc.nu> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Alan Cox Cc: jeff@garzik.org, linux-ide@vger.kernel.org Alan Cox wrote: >> This patch implement ATAPI per-command-type DMA horkages and EH logic >> to set those quickly. This way, failures localized to certain command >> type don't affect other operations (most importantly READs) and >> working configuration is found quickly such that the device can be >> used. > > Seems sensible to treat them differently for different controllers. Have > you considered re-issuing failing ATAPI DMA commands as PIO as an EH > response ? I think determining whether to retry or not belongs to upper layer. Retrying random command can result in unexpected behavior. For things like device/media readiness testing, SCSI / cdrom layer will retry. For pass-through commands, I think it's better to leave it to the application. Thanks. -- tejun