diff options
author | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2015-05-19 15:27:58 +0200 |
---|---|---|
committer | Bjorn Helgaas <bhelgaas@google.com> | 2015-05-21 11:01:12 -0500 |
commit | e705c2959b06b9db184842852da619a0b1672bbc (patch) | |
tree | 420a6a73f9ae44aacd5cd1e8f4e85870469cd8b0 /drivers/pci/hotplug/pciehp_acpi.c | |
parent | 5ebe6afaf0057ac3eaeb98defd5456894b446d22 (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.c | 137 |
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"); -} |