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authorRafael J. Wysocki <rafael.j.wysocki@intel.com>2015-05-19 15:27:58 +0200
committerBjorn Helgaas <bhelgaas@google.com>2015-05-21 11:01:12 -0500
commite705c2959b06b9db184842852da619a0b1672bbc (patch)
tree420a6a73f9ae44aacd5cd1e8f4e85870469cd8b0 /drivers/pci/hotplug/pciehp_acpi.c
parent5ebe6afaf0057ac3eaeb98defd5456894b446d22 (diff)
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>
Diffstat (limited to 'drivers/pci/hotplug/pciehp_acpi.c')
-rw-r--r--drivers/pci/hotplug/pciehp_acpi.c137
1 files changed, 0 insertions, 137 deletions
diff --git a/drivers/pci/hotplug/pciehp_acpi.c b/drivers/pci/hotplug/pciehp_acpi.c
deleted file mode 100644
index 93cc9266e8cb..000000000000
--- 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");
-}