From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Garzik Subject: Re: [PATCH 11/12] (updated) libata-hp-prep: add prereset() method and implement ata_std_prereset() Date: Tue, 30 May 2006 00:12:00 -0400 Message-ID: <447BC610.2000404@pobox.com> References: <11488839571850-git-send-email-htejun@gmail.com> <11488839581576-git-send-email-htejun@gmail.com> <20060529111213.GB30639@htj.dyndns.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from srv5.dvmed.net ([207.36.208.214]:45539 "EHLO mail.dvmed.net") by vger.kernel.org with ESMTP id S1751469AbWE3EML (ORCPT ); Tue, 30 May 2006 00:12:11 -0400 In-Reply-To: <20060529111213.GB30639@htj.dyndns.org> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Tejun Heo Cc: mlord@pobox.com, albertcc@tw.ibm.com, alan@lxorguk.ukuu.org.uk, axboe@suse.de, forrest.zhao@intel.com, linux-ide@vger.kernel.org Tejun Heo wrote: > With hotplug, every reset might be a probing reset and thus something > similar to probe_init() is needed. prereset() method is called before > a series of resets to a port and is the counterpart of postreset(). > prereset() can tell EH to use different type of reset or skip reset by > modifying ehc->i.action. > > This patch also implements ata_std_prereset(). Most controllers > should be able to use this function directly or with some wrapping. > After hotplug, different controllers need different actions to resume > the PHY and detect the newly attached device. Controllers can be > categorized as follows. > > * Controllers which can wait for the first FIS34 after hotplug. Note > that if the waiting is implemented by polling TF status, there needs > to be a way to set BSY on PHY status change. It can be implemented > by hardware or with the help of the driver. > > * Controllers which can wait for the first FIS34 after sending > COMRESET. These controllers need to issue COMRESET to wait for the > first FIS. Note that the received FIS34 could be the first FIS34 > after POR (power-on-reset) or FIS34 in response to the COMRESET. > Some controllers use COMRESET as TF status synchronization point and > clear TF automatically (sata_sil). > > * Controllers which cannot wait for the first FIS34 reliably. Blindly > issuing SRST to spinning-up device often results in command issue > failure or timeout, causing extended delay. For these controllers, > ata_std_prereset() explicitly waits ATA_SPINUP_WAIT (currently 8s) > to give newly attached device time to spin up, then issues reset. > Note that failing to getting ready in ATA_SPINUP_WAIT is not > critical. libata will retry. So, the timeout needs to be long > enough to spin up most devices. > > LLDDs can tell ata_std_prereset() which of above action is needed with > ATA_FLAG_HRST_TO_RESUME and ATA_FLAG_CANT_WAIT_FIS34 flags. These > flags are PHY-specific property and will be moved to ata_link later. > > While at it, this patch unifies function typedef's such that they all > have named arguments. > > Signed-off-by: Tejun Heo ACK, provided that you banish all mentions of "FIS34" from the patch description. "D2H FIS" is far more understandable to the average human. Jeff