From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: Re: How to make SATA hotplug path tight? Date: Tue, 19 Sep 2006 12:11:46 +0900 Message-ID: <450F5FF2.9030208@gmail.com> References: <8202f4270609150812r654c1319r511b18aadf7e1f7@mail.gmail.com> <20060915180903.GC25800@htj.dyndns.org> <8202f4270609151248k236d6c24vab519b64902f102e@mail.gmail.com> <450B58C9.7010904@gmail.com> <8202f4270609181218h160b8df7x4853f58429229b3b@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from wx-out-0506.google.com ([66.249.82.226]:22712 "EHLO wx-out-0506.google.com") by vger.kernel.org with ESMTP id S1751197AbWISDLw (ORCPT ); Mon, 18 Sep 2006 23:11:52 -0400 Received: by wx-out-0506.google.com with SMTP id s14so4275164wxc for ; Mon, 18 Sep 2006 20:11:52 -0700 (PDT) In-Reply-To: <8202f4270609181218h160b8df7x4853f58429229b3b@mail.gmail.com> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Fajun Chen Cc: "linux-ide@vger.kernel.org" [adding linux-ide back, please don't drop it] Fajun Chen wrote: > Hi Tejun, > > I try to understand your eh code and still have several questions: > > 1. Why software is needed after hard reset under certain condition? Because some controllers including sil24 cannot acquire device signature after hardreset. > rc = ata_do_reset(ap, reset, classes); > did_followup_srst = 0; > if (reset == hardreset && > ata_eh_followup_srst_needed(rc, classify, classes)) { > /* okay, let's do follow-up softreset */ > did_followup_srst = 1; > reset = softreset; > ... > Sometimes this part of the code costed as many as 7 secs: > [ 366.400000] ata2: hard resetting port > [ 366.400000] sata_phy_debounce: ENTER > [ 368.490000] sata_phy_debounce: EXIT > [ 368.490000] sil24_softreset: ENTER > [ 375.750000] ata_dev_classify: found ATA device by sig > [ 375.750000] sil24_softreset: EXIT, class=1 > Is there any way to get drive going without going through this? Well, on hotplug case, you need to detect which class of device is attached, so you need a softreset there. > 2. What's the concept of port suspend and resume? Port being suspended and resumed, I think. :-) You need ask more specifically. -- tejun