From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: Re: [PATCH v3] ata: increase retry count but shorten duration for Calxeda controller Date: Sun, 2 Jun 2013 01:00:10 -0700 Message-ID: <20130602080010.GB8286@mtj.dyndns.org> References: <1369842679-9680-1-git-send-email-mark.langsdorf@calxeda.com> <1370014046-5202-1-git-send-email-mark.langsdorf@calxeda.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mail-pb0-f53.google.com ([209.85.160.53]:39643 "EHLO mail-pb0-f53.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750913Ab3FBIAQ (ORCPT ); Sun, 2 Jun 2013 04:00:16 -0400 Content-Disposition: inline In-Reply-To: <1370014046-5202-1-git-send-email-mark.langsdorf@calxeda.com> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Mark Langsdorf Cc: timur@tabi.org, linux-kernel@vger.kernel.org, linux-ide@vger.kernel.org, clemens@ladisch.de, sergei.shtylyov@cogentembedded.com On Fri, May 31, 2013 at 10:27:26AM -0500, Mark Langsdorf wrote: > The Calxeda SATA phy intermittently fails to bring up a link with Gen3 > Retrying the phy hard reset can work around the issue, but the drive > may fail again. In less than 150 out of 15000 test runs, it took more > than 10 tries for the link to be established (but never more than 35). > Triple the maximum observed retry count to provide plenty of margin for > rare events and to guarantee that the link is established. > > Also, the default 2 second time-out on a failed drive is too long in > this situation. The uboot implementation of the same driver function > uses a much shorter time-out period and never experiences a time out > issue. Shorten the Linux time-out value for this driver to 500 ms and > keep the other timing constants the same as the stock AHCI driver. This > change was also tested 15000 times on 24 drives and none of them > experienced a time out. For the third time, explain the above in the comment; otherwise, it's not going in. -- tejun