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author | Ajaykumar Hotchandani <ajaykumar.hotchandani@oracle.com> | 2011-12-12 09:27:36 +0100 |
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committer | Jesse Barnes <jbarnes@virtuousgeek.org> | 2011-12-14 17:26:42 +0100 |
commit | b51306c63449d7f06ffa689036ba49eb46e898b5 (patch) | |
tree | 6f3ad6817681c1ee2a7d7abc86d85695564924ea /drivers/pci/pci.c | |
parent | PCI hotplug: Always allow acpiphp to handle non-PCIe bridges (diff) | |
download | linux-b51306c63449d7f06ffa689036ba49eb46e898b5.tar.xz linux-b51306c63449d7f06ffa689036ba49eb46e898b5.zip |
PCI: Set device power state to PCI_D0 for device without native PM support
During test of one IB card with guest VM, found that, msi is not
initialized properly.
It turns out __write_msi_msg will do nothing if device current_state is
not PCI_D0. And, that pci device does not have pm_cap in guest VM.
There is an error in setting of power state to PCI_D0 in
pci_enable_device(), but error is not returned for this. Following is
code flow:
pci_enable_device() --> __pci_enable_device_flags() -->
do_pci_enable_device() --> pci_set_power_state() -->
__pci_start_power_transition()
We have following condition inside __pci_start_power_transition():
if (platform_pci_power_manageable(dev)) {
error = platform_pci_set_power_state(dev, state);
if (!error)
pci_update_current_state(dev, state);
} else {
error = -ENODEV;
/* Fall back to PCI_D0 if native PM is not supported */
if (!dev->pm_cap)
dev->current_state = PCI_D0;
}
Here, from platform_pci_set_power_state(), acpi_pci_set_power_state() is
getting called and that is failing with ENODEV because of following
condition:
if (!handle || ACPI_SUCCESS(acpi_get_handle(handle, "_EJ0",&tmp)))
return -ENODEV;
Because of that, pci_update_current_state() is not getting called.
With this patch, if device power state can not be set via
platform_pci_set_power_state and that device does not have native pm
support, then PCI device power state will be set to PCI_D0.
-v2: This also reverts 47e9037ac16637cd7f12b8790ea7ce6680e42168, as it's
not needed after this change.
Acked-by: "Rafael J. Wysocki" <rjw@sisk.pl>
Signed-off-by: Ajaykumar Hotchandani<ajaykumar.hotchandani@oracle.com>
Signed-off-by: Yinghai Lu<yinghai.lu@oracle.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Diffstat (limited to 'drivers/pci/pci.c')
-rw-r--r-- | drivers/pci/pci.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 4788413f43d7..faccb8937706 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -664,6 +664,9 @@ static int pci_platform_power_transition(struct pci_dev *dev, pci_power_t state) error = platform_pci_set_power_state(dev, state); if (!error) pci_update_current_state(dev, state); + /* Fall back to PCI_D0 if native PM is not supported */ + if (!dev->pm_cap) + dev->current_state = PCI_D0; } else { error = -ENODEV; /* Fall back to PCI_D0 if native PM is not supported */ |