PCI/PM: Don't sleep at all when d3_delay or d3cold_delay is zero

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.

Do not sleep at all for the respective cases if d3_delay is zero or
d3cold_delay is zero.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 7904d02ffdb97e5f23d915e9c83edbf599ddf58b..9779483f81fdadc0d527069583d7f6c29531cb29 100644 (file)
--- 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