From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0A0C0C32774 for ; Fri, 27 Sep 2019 08:41:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BEE2C21906 for ; Fri, 27 Sep 2019 08:41:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726104AbfI0Ili (ORCPT ); Fri, 27 Sep 2019 04:41:38 -0400 Received: from relay9-d.mail.gandi.net ([217.70.183.199]:37327 "EHLO relay9-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725882AbfI0Ilh (ORCPT ); Fri, 27 Sep 2019 04:41:37 -0400 X-Originating-IP: 65.39.69.237 Received: from localhost (unknown [65.39.69.237]) (Authenticated sender: repk@triplefau.lt) by relay9-d.mail.gandi.net (Postfix) with ESMTPSA id B7CF2FF80F; Fri, 27 Sep 2019 08:41:34 +0000 (UTC) Date: Fri, 27 Sep 2019 10:50:00 +0200 From: Remi Pommarel To: Thomas Petazzoni Cc: Lorenzo Pieralisi , Bjorn Helgaas , linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] PCI: aardvark: Don't rely on jiffies while holding spinlock Message-ID: <20190927084959.GC1208@voidbox.localdomain> References: <20190927083142.8571-1-repk@triplefau.lt> <20190927103420.48bb9335@windsurf> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190927103420.48bb9335@windsurf> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Thomas, On Fri, Sep 27, 2019 at 10:34:20AM +0200, Thomas Petazzoni wrote: > Hello Remi, > > Thanks for the new iteration! > > On Fri, 27 Sep 2019 10:31:42 +0200 > Remi Pommarel wrote: > > > diff --git a/drivers/pci/controller/pci-aardvark.c b/drivers/pci/controller/pci-aardvark.c > > index fc0fe4d4de49..ee05ccb2b686 100644 > > --- a/drivers/pci/controller/pci-aardvark.c > > +++ b/drivers/pci/controller/pci-aardvark.c > > @@ -175,7 +175,8 @@ > > (PCIE_CONF_BUS(bus) | PCIE_CONF_DEV(PCI_SLOT(devfn)) | \ > > PCIE_CONF_FUNC(PCI_FUNC(devfn)) | PCIE_CONF_REG(where)) > > > > -#define PIO_TIMEOUT_MS 1 > > +#define PIO_RETRY_CNT 10 > > +#define PIO_RETRY_DELAY 2 /* 2 us*/ > > So this changes the timeout from 1ms to just 20us, a division by 50 > from the previous timeout value. From my measurements, it could > sometime take up to 6us from a single PIO read operation to complete, > which is getting close to the 20us timeout. > > Shouldn't PIO_RETRY_CNT be kept at 500, so that we keep using a 1ms > timeout ? Damn. You right of course, sorry about that. Thanks -- Remi