From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: 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 -v2] PCI,pciehp: Not write linkctrl register if val is not changed Date: Thu, 23 Feb 2017 13:37:47 -0800 Message-Id: <20170223213747.12154-1-yinghai@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: 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. -v2: inline __pciehp_link_set into pciehp_link_enable Signed-off-by: Yinghai Lu --- drivers/pci/hotplug/pciehp_hpc.c | 19 +++++++------------ 1 file changed, 7 insertions(+), 12 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 @@ -333,28 +333,23 @@ int pciehp_check_link_status(struct cont return 0; } -static int __pciehp_link_set(struct controller *ctrl, bool enable) +static int pciehp_link_enable(struct controller *ctrl) { 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; + lnk_ctrl &= ~PCI_EXP_LNKCTL_LD; + if (old_lnk_ctrl == lnk_ctrl) + return 0; - pcie_capability_write_word(pdev, PCI_EXP_LNKCTL, lnk_ctrl); ctrl_dbg(ctrl, "%s: lnk_ctrl = %x\n", __func__, lnk_ctrl); + pcie_capability_write_word(pdev, PCI_EXP_LNKCTL, lnk_ctrl); return 0; } -static int pciehp_link_enable(struct controller *ctrl) -{ - return __pciehp_link_set(ctrl, true); -} - int pciehp_get_raw_indicator_status(struct hotplug_slot *hotplug_slot, u8 *status) {