On Tuesday, November 26, 2013 05:33:28 PM Toshi Kani wrote:
> On Wed, 2013-11-27 at 01:27 +0100, Rafael J. Wysocki wrote:
> > On Tuesday, November 26, 2013 05:00:42 PM Toshi Kani wrote:
> > > On Mon, 2013-11-25 at 01:09 +0100, Rafael J. Wysocki wrote:
> > > > Hi,
> > > >
> > > > The following series of four patches (on top of current linux-pm.git/bleeding-edge)
> > > > rework child device lookup in drivers/acpi/glue.c and related things:
> > > >
> > > > [1/4] ACPI / bind: Simplify child device lookup
> > > > [2/4] PCI/ ACPI: Use acpi_find_child_device() for child device lookup
> > > > [3/4] ACPI / bind: Redefine acpi_get_child()
> > > > [4/4] ACPI / bind: Redefine acpi_preset_companion()
> > >
> > > This patchset caused the attached panic during boot on a system.
> > > acpi_pci_find_device() called acpi_find_child_device() with
> > > ACPI_COMPANION(dev->parent) being a NULL pointer when scanning bus 0xf.
> > >
> > > This bus 0xf seems to be a chipset internal bus, which is not intended
> > > for the OS to use. Therefore, ACPI does not list its PCI bridge device.
> > >
> > > # lspci -tv
> > > :
> > > +-[0000:0f]-+-08.0 Intel Corporation Ivytown QPI Link 0
> > > | +-08.2 Intel Corporation Ivytown QPI Link 0
> > > :
> > >
> > > However, pcibios_fixup_peer_bridges(), called from pci_subsys_init(),
> > > finds this bus as it scans all the buses from 0 to pcibios_last_bus.
> > > Hence, this dev->parent does not have an associated ACPI device object.
> >
> > Thanks for the report!
> >
> > I've dropped the patches from bleeding-edge for now.
> >
> > Does "[1/4] ACPI / bind: Simplify child device lookup" alone work on that
> > system?
>
> Yes, the system boots fine with 1/4 alone.
Thanks!
Can you please check if the following modified [2/4] also works on top of it?
Rafael
---
From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Subject: PCI / ACPI: Use acpi_find_child_device() for child devices lookup
It is much more efficient to use acpi_find_child_device()
for child devices lookup in acpi_pci_find_device() and pass
ACPI_COMPANION(dev->parent) to it directly instead of obtaining
ACPI_HANDLE() of ACPI_COMPANION(dev->parent) and passing it to
acpi_find_child() which has to run acpi_bus_get_device() to
obtain ACPI_COMPANION(dev->parent) from that again.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Reviewed-by: Aaron Lu <aaron.lu@xxxxxxxxx>
---
drivers/acpi/glue.c | 3 +++
drivers/pci/pci-acpi.c | 16 ++++++++++------
2 files changed, 13 insertions(+), 6 deletions(-)
Index: linux-pm/drivers/pci/pci-acpi.c
===================================================================
--- linux-pm.orig/drivers/pci/pci-acpi.c
+++ linux-pm/drivers/pci/pci-acpi.c
@@ -309,7 +309,8 @@ void acpi_pci_remove_bus(struct pci_bus
static int acpi_pci_find_device(struct device *dev, acpi_handle *handle)
{
struct pci_dev *pci_dev = to_pci_dev(dev);
- bool is_bridge;
+ struct acpi_device *adev;
+ bool check_children;
u64 addr;
/*
@@ -317,14 +318,17 @@ static int acpi_pci_find_device(struct d
* is set only after acpi_pci_find_device() has been called for the
* given device.
*/
- is_bridge = pci_dev->hdr_type == PCI_HEADER_TYPE_BRIDGE
+ check_children = pci_dev->hdr_type == PCI_HEADER_TYPE_BRIDGE
|| pci_dev->hdr_type == PCI_HEADER_TYPE_CARDBUS;
/* Please ref to ACPI spec for the syntax of _ADR */
addr = (PCI_SLOT(pci_dev->devfn) << 16) | PCI_FUNC(pci_dev->devfn);
- *handle = acpi_find_child(ACPI_HANDLE(dev->parent), addr, is_bridge);
- if (!*handle)
- return -ENODEV;
- return 0;
+ adev = acpi_find_child_device(ACPI_COMPANION(dev->parent), addr,
+ check_children);
+ if (adev) {
+ *handle = adev->handle;
+ return 0;
+ }
+ return -ENODEV;
}
static void pci_acpi_setup(struct device *dev)
Index: linux-pm/drivers/acpi/glue.c
===================================================================
--- linux-pm.orig/drivers/acpi/glue.c
+++ linux-pm/drivers/acpi/glue.c
@@ -106,6 +106,9 @@ struct acpi_device *acpi_find_child_devi
struct acpi_device *adev, *ret = NULL;
int ret_score = 0;
+ if (!parent)
+ return NULL;
+
list_for_each_entry(adev, &parent->children, node) {
unsigned long long addr;
acpi_status status;
--
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