From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mark Lord Subject: Re: [PATCH 3/3] Add disk hotswap support to libata RESEND #2 Date: Fri, 16 Sep 2005 12:11:52 -0400 Message-ID: <432AEEC8.3030800@rtr.ca> References: <355e5e5e05080103021a8239df@mail.gmail.com> <4789af9e050823124140eb924f@mail.gmail.com> <4789af9e050823154364c8e9eb@mail.gmail.com> <430BA990.9090807@mvista.com> <430BCB41.5070206@s5r6.in-berlin.de> <355e5e5e05082407031138120a@mail.gmail.com> <4789af9e05082408111c4a6294@mail.gmail.com> <4789af9e05082409121cc6870@mail.gmail.com> <4789af9e0508291223435f174@mail.gmail.com> <4789af9e05090612023fb8517c@mail.gmail.com> <355e5e5e050914214025feee82@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from cpu1185.adsl.bellglobal.com ([207.236.110.166]:23709 "EHLO mail.rtr.ca") by vger.kernel.org with ESMTP id S1161173AbVIPQLx (ORCPT ); Fri, 16 Sep 2005 12:11:53 -0400 In-Reply-To: <355e5e5e050914214025feee82@mail.gmail.com> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: lkosewsk@gmail.com Cc: jim.ramsay@gmail.com, Stefan Richter , linux-scsi@vger.kernel.org, linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org Lukasz Kosewski wrote: > On 9/6/05, Jim Ramsay wrote: > >>However, I have seen the occasion where a single IRQ is used to signal >>both a DMA completion AND a hotplug event. Of course in this case the >>hotplug event itself would be ignored completely. >> >>So I would recommend getting rid of that check entirely. > > > Hey Jim, > > Not that I disbelieve you, but do you have an example of a controller > where this happens? I've done a lot of testing and never seen this... I missed the beginning of this discussion, but here's a data point: The QStor SATA/RAID controller hardware fully supports hotplug (and NCQ, TCQ, Host-Queuing, RAID 0/1/10, PM, etc..). It uses a single interrupt for all onboard events from the four channels. An internal "status FIFO" provides a readout for the interrupt handler of recent happenings, in sequence, mixing together DMA-completions with hotplug-events (insert, removal) and various fault-conditions. All of this is supported in the out-of-tree qstor driver, but only simple single-IO is supported by sata_qstor at present. Dunno if that info is of any use to you in hotplug considerations. Once the libata infrastructure for hotplug is in place, I *may* experiment with adding that functionality to sata_qstor. Cheers