Revert "PCI: pciehp: Add runtime PM support for PCIe hotplug ports"

This reverts commit 68db9bc814362e7f24371c27d12a4f34477d9356.

Yinghai reported that the following manual hotplug sequence:

  # echo 0 > /sys/bus/pci/slots/8/power
  # echo 1 > /sys/bus/pci/slots/8/power

worked in v4.9, but fails in v4.10-rc1, and that reverting 68db9bc81436
("PCI: pciehp: Add runtime PM support for PCIe hotplug ports") makes it
work again.

Fixes: 68db9bc81436 ("PCI: pciehp: Add runtime PM support for PCIe hotplug ports")
Link: https://lkml.kernel.org/r/CAE9FiQVCMCa7iVyuwp9z6VrY0cE7V_xghuXip28Ft52=8QmTWw@mail.gmail.com
Link: https://bugzilla.kernel.org/show_bug.cgi?id=193951
Reported-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

diff --git a/drivers/pci/hotplug/pciehp_ctrl.c b/drivers/pci/hotplug/pciehp_ctrl.c
index 10c9c0b..ec0b4c1 100644 (file)
--- a/drivers/pci/hotplug/pciehp_ctrl.c
+++ b/drivers/pci/hotplug/pciehp_ctrl.c
@@ -31,7 +31,6 @@
 #include <linux/kernel.h>
 #include <linux/types.h>
 #include <linux/slab.h>
-#include <linux/pm_runtime.h>
 #include <linux/pci.h>
 #include "../pci.h"
 #include "pciehp.h"
@@ -99,7 +98,6 @@ static int board_added(struct slot *p_slot)
        pciehp_green_led_blink(p_slot);
 
        /* Check link training status */
-       pm_runtime_get_sync(&ctrl->pcie->port->dev);
        retval = pciehp_check_link_status(ctrl);
        if (retval) {
                ctrl_err(ctrl, "Failed to check link status\n");
@@ -120,14 +118,12 @@ static int board_added(struct slot *p_slot)
                if (retval != -EEXIST)
                        goto err_exit;
        }
-       pm_runtime_put(&ctrl->pcie->port->dev);
 
        pciehp_green_led_on(p_slot);
        pciehp_set_attention_status(p_slot, 0);
        return 0;
 
 err_exit:
-       pm_runtime_put(&ctrl->pcie->port->dev);
        set_slot_off(ctrl, p_slot);
        return retval;
 }
@@ -141,9 +137,7 @@ static int remove_board(struct slot *p_slot)
        int retval;
        struct controller *ctrl = p_slot->ctrl;
 
-       pm_runtime_get_sync(&ctrl->pcie->port->dev);
        retval = pciehp_unconfigure_device(p_slot);
-       pm_runtime_put(&ctrl->pcie->port->dev);
        if (retval)
                return retval;
 

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index a881c0d..7904d02 100644 (file)
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -2241,10 +2241,13 @@ bool pci_bridge_d3_possible(struct pci_dev *bridge)
                        return false;
 
                /*
-                * Hotplug ports handled by firmware in System Management Mode
+                * Hotplug interrupts cannot be delivered if the link is down,
+                * so parents of a hotplug port must stay awake. In addition,
+                * hotplug ports handled by firmware in System Management Mode
                 * may not be put into D3 by the OS (Thunderbolt on non-Macs).
+                * For simplicity, disallow in general for now.
                 */
-               if (bridge->is_hotplug_bridge && !pciehp_is_native(bridge))
+               if (bridge->is_hotplug_bridge)
                        return false;
 
                if (pci_bridge_d3_force)
@@ -2276,10 +2279,7 @@ static int pci_dev_check_d3cold(struct pci_dev *dev, void *data)
             !pci_pme_capable(dev, PCI_D3cold)) ||
 
            /* If it is a bridge it must be allowed to go to D3. */
-           !pci_power_manageable(dev) ||
-
-           /* Hotplug interrupts cannot be delivered if the link is down. */
-           dev->is_hotplug_bridge)
+           !pci_power_manageable(dev))
 
                *d3cold_ok = false;