From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: Re: [PATCH v2 1/2] libata: Add support for SEND/RECEIVE FPDMA QUEUED Date: Fri, 9 Aug 2013 12:18:39 -0400 Message-ID: <20130809161839.GS20515@mtj.dyndns.org> References: <1375946182-2831-1-git-send-email-marc.ceeeee@gmail.com> <1375946182-2831-2-git-send-email-marc.ceeeee@gmail.com> <5203DAD0.6040604@cogentembedded.com> <5203EB9B.3050206@cogentembedded.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mail-qa0-f47.google.com ([209.85.216.47]:54153 "EHLO mail-qa0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934227Ab3HIQSo (ORCPT ); Fri, 9 Aug 2013 12:18:44 -0400 Received: by mail-qa0-f47.google.com with SMTP id o19so979958qap.20 for ; Fri, 09 Aug 2013 09:18:43 -0700 (PDT) Content-Disposition: inline In-Reply-To: <5203EB9B.3050206@cogentembedded.com> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Sergei Shtylyov Cc: Marc C , linux-ide@vger.kernel.org On Thu, Aug 08, 2013 at 11:03:55PM +0400, Sergei Shtylyov wrote: > Hello. > > On 08/08/2013 10:58 PM, Marc C wrote: > > >> How about non-AHCI FIS-based controllers? > > >Right. Since it's cost prohibitive for me to test exhaustively on > >non-AHCI FIS-based controllers, do you think it would be acceptable to > > You can mark your patch as RFT (request for testing) in this case. > > >add a new ATA host flag... something like, ATA_FLAG_AHCI, which would > >denote the controller as being AHCI-based? Then the flag could be used > >to gate processing of READ/WRITE/SEND/RECEIVE FPDMA commands that have > >the 'auxiliary' field set. Or, I could add a big fat warning print > >whenever an ata_queued_cmd is passed to the drivers with a non-zero > >'auxiliary' value. > > I was rather thinking about a flag (ATA_FLAG_FIS_BASED, maybe) > marking a controller as FIS-based, so that libata would know whether > it can issue the new commands using the 'auxiliary' value. I'm not sure whether checking whether a controller is FIS based would be enough. sil24 is clearly FIS based but it snoops the command code and likely to choke on commands which it doesn't know about. I think the best way to deal with it would be having a feature flag on the host / port and setting it on controllers known to work. In practice, just enabling it on ahci's should cover most use cases from now on anyway. Thanks. -- tejun