Re: [BUG] WARN_ON(!context) in drivers/pci/hotplug/acpiphp_glue.c

Steven Rostedt
2013-10-11T13:01:53Z

On Fri, 11 Oct 2013 13:13:47 +0200
"Rafael J. Wysocki" <rjw@rjwysocki.net> wrote:
>
> From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> Subject: ACPI / hotplug / PCI: Accept coexistence with native PCIe hotplug
>
> Allow ACPIPHP (ACPI-based PCI hotplug) to handle event signaling for
> devices that have already been claimed by the native PCIe hotplug
> (pciehp).
>
> The ACPI hotplug events are essentially re-scan, remove and eject
> requests. Re-scan and remove should work regardless, because they
> may be triggered by user space via sysfs and the ACPI eject (_EJ0)
> should work if the BIOS wants us to use it. There may be an issue
> if the BIOS signals ACPI eject and wants us to use the native eject,
> but that doesn't work without this change anyway.
>
> This change prevents the WARN_ON() in acpiphp_enumerate_slots() from
> triggering unnecessarily for bridges whose parents are managed by
> pciehp.
>

Reported-by: Steven Rostedt <rostedt@goodmis.org>
Tested-by: Steven Rostedt <rostedt@goodmis.org>

-- Steve

> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> ---
> drivers/pci/hotplug/acpiphp_glue.c | 32 ++++++++++++++++++++++++++------
> 1 file changed, 26 insertions(+), 6 deletions(-)
>
> Index: linux-pm/drivers/pci/hotplug/acpiphp_glue.c
> ===================================================================
> --- linux-pm.orig/drivers/pci/hotplug/acpiphp_glue.c
> +++ linux-pm/drivers/pci/hotplug/acpiphp_glue.c
> @@ -259,6 +259,31 @@ static void acpiphp_dock_release(void *d
> put_bridge(context->func.parent);
> }
>
> +/**
> + * slot_should_be_exposed - Check whether or not to expose a slot to userland.
> + * @bridge: ACPIPHP bridge the slot belongs to.
> + * @handle: ACPI handle of a device in the slot.
> + */
> +static inline bool slot_should_be_exposed(struct acpiphp_bridge *bridge,
> + acpi_handle handle)
> +{
> + struct pci_bus *pbus = bridge->pci_bus;
> + struct pci_dev *pdev = bridge->pci_dev;
> +
> + /*
> + * Do not expose slots whose bridges are managed by pciehp, because they
> + * will be exposed to user space by the pciehp driver.
> + */
> + if (pdev && device_is_managed_by_native_pciehp(pdev))
> + return false;
> +
> + /*
> + * Expose slots for devices with either _EJ0 or _RMV and for devices
> + * on docking stations.
> + */
> + return acpi_pci_check_ejectable(pbus, handle) || is_dock_device(handle);
> +}
> +
> /* callback routine to register each ACPI PCI slot object */
> static acpi_status register_slot(acpi_handle handle, u32 lvl, void *data,
> void **rv)
> @@ -271,12 +296,8 @@ static acpi_status register_slot(acpi_ha
> unsigned long long adr;
> int device, function;
> struct pci_bus *pbus = bridge->pci_bus;
> - struct pci_dev *pdev = bridge->pci_dev;
> u32 val;
>
> - if (pdev && device_is_managed_by_native_pciehp(pdev))
> - return AE_OK;
> -
> status = acpi_evaluate_integer(handle, "_ADR", NULL, &adr);
> if (ACPI_FAILURE(status)) {
> acpi_handle_warn(handle, "can't evaluate _ADR (%#x)\n", status);
> @@ -325,8 +346,7 @@ static acpi_status register_slot(acpi_ha
>
> list_add_tail(&slot->node, &bridge->slots);
>
> - /* Register slots for ejectable funtions only. */
> - if (acpi_pci_check_ejectable(pbus, handle) || is_dock_device(handle)) {
> + if (slot_should_be_exposed(bridge, handle)) {
> unsigned long long sun;
> int retval;
>