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[209.132.180.67]) by mx.google.com with ESMTP id rk14si6910366ejb.24.2019.10.12.00.35.05; Sat, 12 Oct 2019 00:35:28 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=llaxfXY8; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728861AbfJLHet (ORCPT + 99 others); Sat, 12 Oct 2019 03:34:49 -0400 Received: from mail-pg1-f195.google.com ([209.85.215.195]:38312 "EHLO mail-pg1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727115AbfJLHet (ORCPT ); Sat, 12 Oct 2019 03:34:49 -0400 Received: by mail-pg1-f195.google.com with SMTP id w3so167631pgt.5; Sat, 12 Oct 2019 00:34:48 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=5zqQxbggLDLgvUgrs/8xb+vZbp9BeRehGvstEP4vmcU=; b=llaxfXY8WP09S7WoyOdiqe5wZ7iEb5yrB0ES1XuXYGPOxBd0r+PvyP68XLLA43cc4S NkFu5QhcFXMdRGCvJ2WyIKsk+6NEUvFUYjfFe/KYwwyVn20zd1RsWwJp5Mn7Ww1MQCK6 8eooj4hVKn7Cyfw4hUgfYxEymGVwcmhp0H1XhsPHqnmEDr2CCdLAFQ79ggbY95mjJNTg 21Fw8n3PNbshoe12zpEhEzEtpQ/UecnYtNS0wX6D52X9ShKhvT2Q6gRyAKtyEt7CjFV+ MIO7VZiAQitmBRWqfWcqidryoyT8RGoJDz5OK2Btg6BIWMOZSHUKqT+Uvr9onyYCDztH XAwQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=5zqQxbggLDLgvUgrs/8xb+vZbp9BeRehGvstEP4vmcU=; b=QeOe4C7Omxfj2U1c2zcwMpFi8+f8U6UWy/MvmkjyG+UWt0KWkM02huotZIJgUXF60V wImTKhK2rD5+/oKUHz4kp6/FBmc9oU5eQxzU/3Pgz1xED4j4iZKfnEd4jt7DTTEflzTa D1R4uN9741m423gFI7/RMlCdUvDlTOReHnDNx7sflbS74vEod0tWUNA0VAmwD/tHMaPt Xp1vZDlMULf7c4unMq08T68f9456F79AOBz/xsVkWkleZr2S+SUUCTws0VxkyIhL53U0 3dvkYMSE6HbIjRGWJkgXSoo4FkDgg9vIxG6oKgVPcWd4hbmAc90YbFo1Pqo0muynJPJv pfCg== X-Gm-Message-State: APjAAAWBMkfD+N8BxviGitMq/knmgWhYEGgVD3g5SLbxPxXh4T2yikxc sMsFfpCwdh3oQCTIA+qrOztIw4SC8qbDVpYw9D93udB+CN8= X-Received: by 2002:a62:e80b:: with SMTP id c11mr20351462pfi.241.1570865688320; Sat, 12 Oct 2019 00:34:48 -0700 (PDT) MIME-Version: 1.0 References: <20191011205127.4884-1-stuart.w.hayes@gmail.com> <20191011205127.4884-3-stuart.w.hayes@gmail.com> In-Reply-To: <20191011205127.4884-3-stuart.w.hayes@gmail.com> From: Andy Shevchenko Date: Sat, 12 Oct 2019 10:34:35 +0300 Message-ID: Subject: Re: [PATCH v2 2/3] PCI: pciehp: Wait for PDS if in-band presence is disabled To: Stuart Hayes Cc: Bjorn Helgaas , Austin Bolen , Keith Busch , Alexandru Gagniuc , "Rafael J . Wysocki" , Mika Westerberg , "Gustavo A . R . Silva" , Sinan Kaya , Oza Pawandeep , linux-pci@vger.kernel.org, Linux Kernel Mailing List , Lukas Wunner Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Oct 11, 2019 at 11:51 PM Stuart Hayes wrote: > > From: Alexandru Gagniuc > > When inband presence is disabled, PDS may come up at any time, or not > at all. PDS being low may indicate that the card is still mating, and > we could expect contact bounce to bring down the link as well. > > It is reasonable to assume that most cards will mate in a hotplug slot > in about a second. Thus, when we know PDS only reflects out-of-band > presence, it's worthwhile to wait the extra second or so to make sure > the card is properly mated before loading the driver, and to prevent > the hotplug code from disabling a device if the presence detect change > goes active after the device is enabled. Thank you! My comments below. > +static void pcie_wait_for_presence(struct pci_dev *pdev) > +{ > + int timeout = 1250; > + bool pds; make W=1 will issue a warning. Just remove the line. > + u16 slot_status; > + > + do { > + pcie_capability_read_word(pdev, PCI_EXP_SLTSTA, &slot_status); > + if (!!(slot_status & PCI_EXP_SLTSTA_PDS)) > + return; > + msleep(10); > + timeout -= 10; > + } while (timeout > 0); > + > + pci_info(pdev, "Presence Detect state not set in 1250 msec\n"); Perhaps ("%d", timeout) ? > +} -- With Best Regards, Andy Shevchenko