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=-5.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_2 autolearn=ham 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 B5029C4360C for ; Fri, 27 Sep 2019 08:34:37 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 88EAE217F4 for ; Fri, 27 Sep 2019 08:34:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="RCUgK7br" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 88EAE217F4 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=bootlin.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=xBjqkzOt5RReYCxrDY7chv+0S5sruM3BY4Tyf8C9rBs=; b=RCUgK7br+RfAUl 8lWL1Jh1t/SpRR19/rTKfhlsn10IMWhWVVdO7pPQ2tNx8zzV+cBFz9xr4pgIBHbBdkn2PyQBttvd7 f8PQitKNz4N1xRKHE+7CUgTRBsSCJmCrWUwiLiBDz9pwjUjcO60AYB4eeUMJsWGetn9uSQiPkNirQ 6L7tWHb2B6PgX7oSDlxY/RfqfB8l+0tr10xC5bMUvAh1wlLNFDl2qCdyZ56hXzL6Jmgp7wc61rck2 j9ktKyCLvt+vftIviB0sAW+plmNzJWCawGkVlmj7LU3nwEjfv78qe7oSHmGqdZTbcQ8dGGUnaMcHW nnkeTLWLzI89KnOiNk7w==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.2 #3 (Red Hat Linux)) id 1iDlhs-00029o-BC; Fri, 27 Sep 2019 08:34:28 +0000 Received: from relay1-d.mail.gandi.net ([217.70.183.193]) by bombadil.infradead.org with esmtps (Exim 4.92.2 #3 (Red Hat Linux)) id 1iDlhp-00028U-6p for linux-arm-kernel@lists.infradead.org; Fri, 27 Sep 2019 08:34:26 +0000 X-Originating-IP: 86.250.200.211 Received: from windsurf (lfbn-1-17395-211.w86-250.abo.wanadoo.fr [86.250.200.211]) (Authenticated sender: thomas.petazzoni@bootlin.com) by relay1-d.mail.gandi.net (Postfix) with ESMTPSA id 9C4DA24000C; Fri, 27 Sep 2019 08:34:21 +0000 (UTC) Date: Fri, 27 Sep 2019 10:34:20 +0200 From: Thomas Petazzoni To: Remi Pommarel Subject: Re: [PATCH v2] PCI: aardvark: Don't rely on jiffies while holding spinlock Message-ID: <20190927103420.48bb9335@windsurf> In-Reply-To: <20190927083142.8571-1-repk@triplefau.lt> References: <20190927083142.8571-1-repk@triplefau.lt> Organization: Bootlin X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.32; x86_64-redhat-linux-gnu) MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190927_013425_392936_16D72200 X-CRM114-Status: GOOD ( 11.28 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Bjorn Helgaas , linux-pci@vger.kernel.org, Lorenzo Pieralisi , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org 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 ? Thomas -- Thomas Petazzoni, CTO, Bootlin Embedded Linux and Kernel engineering https://bootlin.com _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel