From mboxrd@z Thu Jan 1 00:00:00 1970 From: Adrian Hunter Subject: [PATCH] PCI: For d3_delay and d3cold_delay, zero means zero Date: Tue, 14 Mar 2017 15:21:58 +0200 Message-ID: <1489497718-4099-1-git-send-email-adrian.hunter@intel.com> References: <20170314130305.GH8232@bhelgaas-glaptop.roam.corp.google.com> Return-path: In-Reply-To: <20170314130305.GH8232@bhelgaas-glaptop.roam.corp.google.com> Sender: linux-pci-owner@vger.kernel.org To: Bjorn Helgaas Cc: linux-pci , linux-pm , linux-acpi , "Rafael J. Wysocki" , Lukas Wunner , Andy Shevchenko , Mika Westerberg List-Id: linux-pm@vger.kernel.org msleep() still sleeps 1 jiffy even when told to sleep for zero milliseconds. That can end up being 1-2 milliseconds or more. In the cases of d3_delay and d3cold_delay, that unnecessarily increases suspend and/or resume latencies. So, do not sleep at all for the respective cases of d3_delay is zero or d3cold_delay is zero. Signed-off-by: Adrian Hunter --- drivers/pci/pci.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 7904d02ffdb9..9779483f81fd 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -66,7 +66,8 @@ static void pci_dev_d3_sleep(struct pci_dev *dev) if (delay < pci_pm_d3_delay) delay = pci_pm_d3_delay; - msleep(delay); + if (delay) + msleep(delay); } #ifdef CONFIG_PCI_DOMAINS @@ -827,7 +828,8 @@ static void __pci_start_power_transition(struct pci_dev *dev, pci_power_t state) * because have already delayed for the bridge. */ if (dev->runtime_d3cold) { - msleep(dev->d3cold_delay); + if (dev->d3cold_delay) + msleep(dev->d3cold_delay); /* * When powering on a bridge from D3cold, the * whole hierarchy may be powered on into -- 1.9.1