From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751283AbdBWVct (ORCPT ); Thu, 23 Feb 2017 16:32:49 -0500 Received: from userp1040.oracle.com ([156.151.31.81]:25133 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751201AbdBWVcs (ORCPT ); Thu, 23 Feb 2017 16:32:48 -0500 From: Yinghai Lu To: Bjorn Helgaas Cc: Ashok Raj , james puthukattukaran , Yinghai Lu , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, Yinghai Lu Subject: [PATCH] PCI,pciehp: Not write linkctrl register if val is changed Date: Thu, 23 Feb 2017 13:32:28 -0800 Message-Id: <20170223213228.11467-1-yinghai@kernel.org> X-Mailer: git-send-email 2.8.3 X-Source-IP: aserv0021.oracle.com [141.146.126.233] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Most system have port link enabled by default, and should not have confusing printout. Also move printout before actully write, so could make debug print in order. Signed-off-by: Yinghai Lu --- drivers/pci/hotplug/pciehp_hpc.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) Index: linux-2.6/drivers/pci/hotplug/pciehp_hpc.c =================================================================== --- linux-2.6.orig/drivers/pci/hotplug/pciehp_hpc.c +++ linux-2.6/drivers/pci/hotplug/pciehp_hpc.c @@ -336,17 +336,21 @@ int pciehp_check_link_status(struct cont static int __pciehp_link_set(struct controller *ctrl, bool enable) { struct pci_dev *pdev = ctrl_dev(ctrl); - u16 lnk_ctrl; + u16 lnk_ctrl, old_lnk_ctrl; pcie_capability_read_word(pdev, PCI_EXP_LNKCTL, &lnk_ctrl); + old_lnk_ctrl = lnk_ctrl; if (enable) lnk_ctrl &= ~PCI_EXP_LNKCTL_LD; else lnk_ctrl |= PCI_EXP_LNKCTL_LD; - pcie_capability_write_word(pdev, PCI_EXP_LNKCTL, lnk_ctrl); + if (old_lnk_ctrl == lnk_ctrl) + return 0; + ctrl_dbg(ctrl, "%s: lnk_ctrl = %x\n", __func__, lnk_ctrl); + pcie_capability_write_word(pdev, PCI_EXP_LNKCTL, lnk_ctrl); return 0; }