From patchwork Mon Feb 22 20:05:48 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alex Williamson X-Patchwork-Id: 8382591 X-Patchwork-Delegate: bhelgaas@google.com Return-Path: X-Original-To: patchwork-linux-pci@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 65A3D9F2F0 for ; Mon, 22 Feb 2016 20:05:53 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 83BBC2052A for ; Mon, 22 Feb 2016 20:05:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 84BE420483 for ; Mon, 22 Feb 2016 20:05:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754702AbcBVUFu (ORCPT ); Mon, 22 Feb 2016 15:05:50 -0500 Received: from mx1.redhat.com ([209.132.183.28]:41214 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753498AbcBVUFt (ORCPT ); Mon, 22 Feb 2016 15:05:49 -0500 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) by mx1.redhat.com (Postfix) with ESMTPS id 50BE4C0F56EC; Mon, 22 Feb 2016 20:05:49 +0000 (UTC) Received: from gimli.home (ovpn-113-102.phx2.redhat.com [10.3.113.102]) by int-mx09.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id u1MK5mwI030962; Mon, 22 Feb 2016 15:05:48 -0500 Subject: [PATCH v3] pci: Wait for up to 1000ms after FLR reset From: Alex Williamson To: linux-pci@vger.kernel.org Cc: allen.m.kay@intel.com, linux-kernel@vger.kernel.org, kvm@vger.kernel.org Date: Mon, 22 Feb 2016 13:05:48 -0700 Message-ID: <20160222200351.4709.85363.stgit@gimli.home> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.68 on 10.5.11.22 Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Some devices take longer than the spec indicates to return from FLR reset, a notable case of this is Intel integrated graphics (IGD), which can often take an additional 300ms powering down an attached LCD panel as part of the FLR. Allow devices up to 1000ms, testing every 100ms whether the second dword of config space is read as -1. Signed-off-by: Alex Williamson --- v3: Read 2nd dword since SR-IOV VFs don't implement the 1st dword v2: Change loop to incorporate initial 100ms delay, replace delay in callee functions, add comment. drivers/pci/pci.c | 27 +++++++++++++++++++++++++-- 1 file changed, 25 insertions(+), 2 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 602eb42..365ac76 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -3414,6 +3414,29 @@ int pci_wait_for_pending_transaction(struct pci_dev *dev) } EXPORT_SYMBOL(pci_wait_for_pending_transaction); +/* + * We should only need to wait 100ms after FLR, but some devices take longer. + * Wait for up to 1000ms for config space to return something other than -1. + * Intel IGD requires this when an LCD panel is attached. We read the 2nd + * dword because VFs don't implement the 1st dword. + */ +static void pci_flr_wait(struct pci_dev *dev) +{ + int i = 0; + u32 id; + + do { + msleep(100); + pci_read_config_dword(dev, PCI_COMMAND, &id); + } while (i++ < 10 && id == ~0); + + if (id == ~0) + dev_warn(&dev->dev, "Failed to return from FLR\n"); + else if (i > 1) + dev_info(&dev->dev, "Required additional " + "%dms to return from FLR\n", (i - 1) * 100); +} + static int pcie_flr(struct pci_dev *dev, int probe) { u32 cap; @@ -3429,7 +3452,7 @@ static int pcie_flr(struct pci_dev *dev, int probe) dev_err(&dev->dev, "timed out waiting for pending transaction; performing function level reset anyway\n"); pcie_capability_set_word(dev, PCI_EXP_DEVCTL, PCI_EXP_DEVCTL_BCR_FLR); - msleep(100); + pci_flr_wait(dev); return 0; } @@ -3459,7 +3482,7 @@ static int pci_af_flr(struct pci_dev *dev, int probe) dev_err(&dev->dev, "timed out waiting for pending transaction; performing AF function level reset anyway\n"); pci_write_config_byte(dev, pos + PCI_AF_CTRL, PCI_AF_CTRL_FLR); - msleep(100); + pci_flr_wait(dev); return 0; }