PCI: pciehp: Drop pointless ACPI-based "slot detection" check

Jarod Wilson reports that ExpressCard hotplug doesn't work on HP ZBook G2.
The problem turns out to be the ACPI-based "slot detection" code called
from pciehp_probe() which uses questionable heuristics based on what ACPI
objects are present for the PCIe port device to figure out whether to
register a hotplug slot for that port.

That code is used if there is at least one PCIe port having an ACPI device
configuration object related to hotplug (such as _EJ0 or _RMV), and the
Thunderbolt port on the ZBook has _RMV.  Of course, Thunderbolt and PCIe
native hotplug need not be mutually exclusive (as they aren't on the
ZBook), so that rule is simply incorrect.

Moreover, the ACPI-based "slot detection" check does not add any value if
pciehp_probe() is called at all and the service type of the device object
it has been called for is PCIE_PORT_SERVICE_HP, because PCIe hotplug
services are only registered if the _OSC handshake in acpi_pci_root_add()
allows the kernel to control the PCIe native hotplug feature.  No more
checks need to be carried out to decide whether or not to register a native
PCIe hotlug slot in that case.

For the above reasons, make pciehp_probe() check if it has been called for
the right service type and drop the pointless ACPI-based "slot detection"
check from it.  Also remove the entire code whose only user is that check
(the entire pciehp_acpi.c file goes away as a result) and drop function
headers related to it from the internal pciehp header file.

Link: http://lkml.kernel.org/r/1431632038-39917-1-git-send-email-jarod@redhat.com
Link: https://bugzilla.kernel.org/show_bug.cgi?id=98581
Reported-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Jarod Wilson <jarod@redhat.com>
Tested-by: Jarod Wilson <jarod@redhat.com>

diff --git a/drivers/pci/hotplug/Makefile b/drivers/pci/hotplug/Makefile
index 4a9aa08b08f13600ecad592eb7e452c8ed4132b9..b616e7588ff47da6b9cda4959cdcc891dbd0d5bf 100644 (file)
--- a/drivers/pci/hotplug/Makefile
+++ b/drivers/pci/hotplug/Makefile
@@ -61,9 +61,6 @@ pciehp-objs           :=      pciehp_core.o   \
                                pciehp_ctrl.o   \
                                pciehp_pci.o    \
                                pciehp_hpc.o
-ifdef CONFIG_ACPI
-pciehp-objs            +=      pciehp_acpi.o
-endif
 
 shpchp-objs            :=      shpchp_core.o   \
                                shpchp_ctrl.o   \

diff --git a/drivers/pci/hotplug/pciehp.h b/drivers/pci/hotplug/pciehp.h
index b11521953485bb99892b85dd4c2c3e93378c2d56..ce4d12c4eff4676068a4c1b40c74c493b31f90ee 100644 (file)
--- a/drivers/pci/hotplug/pciehp.h
+++ b/drivers/pci/hotplug/pciehp.h
@@ -167,21 +167,4 @@ static inline const char *slot_name(struct slot *slot)
        return hotplug_slot_name(slot->hotplug_slot);
 }
 
-#ifdef CONFIG_ACPI
-#include <linux/pci-acpi.h>
-
-void __init pciehp_acpi_slot_detection_init(void);
-int pciehp_acpi_slot_detection_check(struct pci_dev *dev);
-
-static inline void pciehp_firmware_init(void)
-{
-       pciehp_acpi_slot_detection_init();
-}
-#else
-#define pciehp_firmware_init()                         do {} while (0)
-static inline int pciehp_acpi_slot_detection_check(struct pci_dev *dev)
-{
-       return 0;
-}
-#endif                         /* CONFIG_ACPI */
 #endif                         /* _PCIEHP_H */

diff --git a/drivers/pci/hotplug/pciehp_acpi.c b/drivers/pci/hotplug/pciehp_acpi.c
deleted file mode 100644 (file)
index 93cc926..0000000
--- a/drivers/pci/hotplug/pciehp_acpi.c
+++ /dev/null
@@ -1,137 +0,0 @@
-/*
- * ACPI related functions for PCI Express Hot Plug driver.
- *
- * Copyright (C) 2008 Kenji Kaneshige
- * Copyright (C) 2008 Fujitsu Limited.
- *
- * All rights reserved.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or (at
- * your option) any later version.
- *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
- * NON INFRINGEMENT.  See the GNU General Public License for more
- * details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
- *
- */
-
-#include <linux/acpi.h>
-#include <linux/pci.h>
-#include <linux/pci_hotplug.h>
-#include <linux/slab.h>
-#include <linux/module.h>
-#include "pciehp.h"
-
-#define PCIEHP_DETECT_PCIE     (0)
-#define PCIEHP_DETECT_ACPI     (1)
-#define PCIEHP_DETECT_AUTO     (2)
-#define PCIEHP_DETECT_DEFAULT  PCIEHP_DETECT_AUTO
-
-struct dummy_slot {
-       u32 number;
-       struct list_head list;
-};
-
-static int slot_detection_mode;
-static char *pciehp_detect_mode;
-module_param(pciehp_detect_mode, charp, 0444);
-MODULE_PARM_DESC(pciehp_detect_mode,
-        "Slot detection mode: pcie, acpi, auto\n"
-        "  pcie          - Use PCIe based slot detection\n"
-        "  acpi          - Use ACPI for slot detection\n"
-        "  auto(default) - Auto select mode. Use acpi option if duplicate\n"
-        "                  slot ids are found. Otherwise, use pcie option\n");
-
-int pciehp_acpi_slot_detection_check(struct pci_dev *dev)
-{
-       if (slot_detection_mode != PCIEHP_DETECT_ACPI)
-               return 0;
-       if (acpi_pci_detect_ejectable(ACPI_HANDLE(&dev->dev)))
-               return 0;
-       return -ENODEV;
-}
-
-static int __init parse_detect_mode(void)
-{
-       if (!pciehp_detect_mode)
-               return PCIEHP_DETECT_DEFAULT;
-       if (!strcmp(pciehp_detect_mode, "pcie"))
-               return PCIEHP_DETECT_PCIE;
-       if (!strcmp(pciehp_detect_mode, "acpi"))
-               return PCIEHP_DETECT_ACPI;
-       if (!strcmp(pciehp_detect_mode, "auto"))
-               return PCIEHP_DETECT_AUTO;
-       warn("bad specifier '%s' for pciehp_detect_mode. Use default\n",
-            pciehp_detect_mode);
-       return PCIEHP_DETECT_DEFAULT;
-}
-
-static int __initdata dup_slot_id;
-static int __initdata acpi_slot_detected;
-static struct list_head __initdata dummy_slots = LIST_HEAD_INIT(dummy_slots);
-
-/* Dummy driver for duplicate name detection */
-static int __init dummy_probe(struct pcie_device *dev)
-{
-       u32 slot_cap;
-       acpi_handle handle;
-       struct dummy_slot *slot, *tmp;
-       struct pci_dev *pdev = dev->port;
-
-       pcie_capability_read_dword(pdev, PCI_EXP_SLTCAP, &slot_cap);
-       slot = kzalloc(sizeof(*slot), GFP_KERNEL);
-       if (!slot)
-               return -ENOMEM;
-       slot->number = (slot_cap & PCI_EXP_SLTCAP_PSN) >> 19;
-       list_for_each_entry(tmp, &dummy_slots, list) {
-               if (tmp->number == slot->number)
-                       dup_slot_id++;
-       }
-       list_add_tail(&slot->list, &dummy_slots);
-       handle = ACPI_HANDLE(&pdev->dev);
-       if (!acpi_slot_detected && acpi_pci_detect_ejectable(handle))
-               acpi_slot_detected = 1;
-       return -ENODEV;         /* dummy driver always returns error */
-}
-
-static struct pcie_port_service_driver __initdata dummy_driver = {
-       .name           = "pciehp_dummy",
-       .port_type      = PCIE_ANY_PORT,
-       .service        = PCIE_PORT_SERVICE_HP,
-       .probe          = dummy_probe,
-};
-
-static int __init select_detection_mode(void)
-{
-       struct dummy_slot *slot, *tmp;
-
-       if (pcie_port_service_register(&dummy_driver))
-               return PCIEHP_DETECT_ACPI;
-       pcie_port_service_unregister(&dummy_driver);
-       list_for_each_entry_safe(slot, tmp, &dummy_slots, list) {
-               list_del(&slot->list);
-               kfree(slot);
-       }
-       if (acpi_slot_detected && dup_slot_id)
-               return PCIEHP_DETECT_ACPI;
-       return PCIEHP_DETECT_PCIE;
-}
-
-void __init pciehp_acpi_slot_detection_init(void)
-{
-       slot_detection_mode = parse_detect_mode();
-       if (slot_detection_mode != PCIEHP_DETECT_AUTO)
-               goto out;
-       slot_detection_mode = select_detection_mode();
-out:
-       if (slot_detection_mode == PCIEHP_DETECT_ACPI)
-               info("Using ACPI for slot detection.\n");
-}

diff --git a/drivers/pci/hotplug/pciehp_core.c b/drivers/pci/hotplug/pciehp_core.c
index 07aa722bb12cd61a6a3a8767b2efe1dd826e6952..5e052981f1c16fbbbbf5779d6d97cc51cdb04cf0 100644 (file)
--- a/drivers/pci/hotplug/pciehp_core.c
+++ b/drivers/pci/hotplug/pciehp_core.c
@@ -248,12 +248,9 @@ static int pciehp_probe(struct pcie_device *dev)
        struct slot *slot;
        u8 occupied, poweron;
 
-       if (pciehp_force)
-               dev_info(&dev->device,
-                        "Bypassing BIOS check for pciehp use on %s\n",
-                        pci_name(dev->port));
-       else if (pciehp_acpi_slot_detection_check(dev->port))
-               goto err_out_none;
+       /* If this is not a "hotplug" service, we have no business here. */
+       if (dev->service != PCIE_PORT_SERVICE_HP)
+               return -ENODEV;
 
        if (!dev->port->subordinate) {
                /* Can happen if we run out of bus numbers during probe */
@@ -366,7 +363,6 @@ static int __init pcied_init(void)
 {
        int retval = 0;
 
-       pciehp_firmware_init();
        retval = pcie_port_service_register(&hpdriver_portdrv);
        dbg("pcie_port_service_register = %d\n", retval);
        info(DRIVER_DESC " version: " DRIVER_VERSION "\n");