From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: Re: [PATCH 4/5] libata: support the ata host which implements a queue depth less than 32 Date: Fri, 4 Jul 2014 11:30:22 -0400 Message-ID: <20140704153022.GA764@mtj.dyndns.org> References: <1404389382-27298-1-git-send-email-haokexin@gmail.com> <1404389382-27298-5-git-send-email-haokexin@gmail.com> <20140703134717.GA16191@htj.dyndns.org> <20140704064646.GA15828@pek-khao-d1.corp.ad.wrs.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mail-qa0-f44.google.com ([209.85.216.44]:48503 "EHLO mail-qa0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751742AbaGDPa0 (ORCPT ); Fri, 4 Jul 2014 11:30:26 -0400 Received: by mail-qa0-f44.google.com with SMTP id hw13so1461998qab.3 for ; Fri, 04 Jul 2014 08:30:26 -0700 (PDT) Content-Disposition: inline In-Reply-To: <20140704064646.GA15828@pek-khao-d1.corp.ad.wrs.com> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Kevin Hao Cc: linux-ide@vger.kernel.org, Dan Williams Hello, Kevin. On Fri, Jul 04, 2014 at 02:46:46PM +0800, Kevin Hao wrote: > Since the fsl sata only support a 16 command queue, if we put the internal > command to ata_port->qcmd[16 - 1], we can easily change the above code to: Hmmm... something that I wanna do is using all 32 tags for regular commands and moving ATA_TAG_INTERNAL to something out-of-bounds, say 32 or INT_MAX and let each driver use whatever command slot (most likely zero) to actually execute internal commands. There really is no reason to permanently reserve a command tag for internal commands like we do now; however, it could be that using a tag number to distinguish an internal command isn't a very good idea to begin with and it could be better to use a qcflag instead. Anyways, sata_fsl already has workaround for ATA_TAG_INTERNAL, right? Given that the situation around internal tag handling may change, I'm not sure about changing the interface now. Is it a lot of cruft on fsl side? Thanks. -- tejun