From patchwork Fri May 31 15:27:26 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Langsdorf X-Patchwork-Id: 247974 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 6FD4A2C007E for ; Sat, 1 Jun 2013 01:27:34 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756122Ab3EaP1d (ORCPT ); Fri, 31 May 2013 11:27:33 -0400 Received: from smtp113.ord1c.emailsrvr.com ([108.166.43.113]:39025 "EHLO smtp113.ord1c.emailsrvr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755399Ab3EaP1c (ORCPT ); Fri, 31 May 2013 11:27:32 -0400 Received: from localhost (localhost.localdomain [127.0.0.1]) by smtp7.relay.ord1c.emailsrvr.com (SMTP Server) with ESMTP id 545DB1B80E0; Fri, 31 May 2013 11:27:31 -0400 (EDT) X-Virus-Scanned: OK Received: by smtp7.relay.ord1c.emailsrvr.com (Authenticated sender: mark.langsdorf-AT-calxeda.com) with ESMTPSA id BC7BA1B80F5; Fri, 31 May 2013 11:27:30 -0400 (EDT) From: Mark Langsdorf To: tj@kernel.org, timur@tabi.org, linux-kernel@vger.kernel.org, linux-ide@vger.kernel.org, clemens@ladisch.de, sergei.shtylyov@cogentembedded.com Cc: Mark Langsdorf Subject: [PATCH v3] ata: increase retry count but shorten duration for Calxeda controller Date: Fri, 31 May 2013 10:27:26 -0500 Message-Id: <1370014046-5202-1-git-send-email-mark.langsdorf@calxeda.com> X-Mailer: git-send-email 1.8.1.2 In-Reply-To: <1369842679-9680-1-git-send-email-mark.langsdorf@calxeda.com> References: <1369842679-9680-1-git-send-email-mark.langsdorf@calxeda.com> Sender: linux-ide-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ide@vger.kernel.org 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. Signed-off-by: Mark Langsdorf --- Changes from v2 Add static to the timing variable definition Changes from v1 Add const to the timing variable definition Added more detail in why the various numbers were chosen drivers/ata/sata_highbank.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/ata/sata_highbank.c b/drivers/ata/sata_highbank.c index b20aa96..46ccc1c 100644 --- a/drivers/ata/sata_highbank.c +++ b/drivers/ata/sata_highbank.c @@ -199,7 +199,7 @@ static int highbank_initialize_phys(struct device *dev, void __iomem *addr) static int ahci_highbank_hardreset(struct ata_link *link, unsigned int *class, unsigned long deadline) { - const unsigned long *timing = sata_ehc_deb_timing(&link->eh_context); + static const unsigned long timing[] = { 5, 100, 500}; struct ata_port *ap = link->ap; struct ahci_port_priv *pp = ap->private_data; u8 *d2h_fis = pp->rx_fis + RX_FIS_D2H_REG; @@ -207,7 +207,7 @@ static int ahci_highbank_hardreset(struct ata_link *link, unsigned int *class, bool online; u32 sstatus; int rc; - int retry = 10; + int retry = 100; ahci_stop_engine(ap);