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authorHuang Ying <ying.huang@intel.com>2012-08-08 09:07:39 +0800
committerBjorn Helgaas <bhelgaas@google.com>2012-08-21 17:32:07 -0600
commitea8c88f13d9fb1d6b39a05bfa07ae076ca1c6803 (patch)
treeb063ab2cc5c779bf5f9ba7d92514dbfb04d64360 /drivers/pci
parent4f9c1397e2e80e52b17ec4e39760caa807bd15c7 (diff)
PCI/PM: Keep parent bridge active when probing device
This patch fixes the following bug: http://marc.info/?l=linux-pci&m=134329923124234&w=2 The root cause of the bug is as follow. If a device is not bound with the corresponding driver, the device runtime PM will be disabled and the device will be put into suspended state. So that, the bridge/PCIe port connected to it may be put into suspended and low power state. When do probing for the device later, because the bridge/PCIe port connected to it is in low power state, the IO access to device may fail. To solve the issue, the bridge/PCIe port connected to the device is put into active state before probing. Reported-by: Bjorn Mork <bjorn@mork.no> Signed-off-by: Huang Ying <ying.huang@intel.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Rafael J. Wysocki <rjw@sisk.pl>
Diffstat (limited to 'drivers/pci')
-rw-r--r--drivers/pci/pci-driver.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
index 5270f1a9932..d6fd6b6d9d4 100644
--- a/drivers/pci/pci-driver.c
+++ b/drivers/pci/pci-driver.c
@@ -280,8 +280,12 @@ static long local_pci_probe(void *_ddi)
{
struct drv_dev_and_id *ddi = _ddi;
struct device *dev = &ddi->dev->dev;
+ struct device *parent = dev->parent;
int rc;
+ /* The parent bridge must be in active state when probing */
+ if (parent)
+ pm_runtime_get_sync(parent);
/* Unbound PCI devices are always set to disabled and suspended.
* During probe, the device is set to enabled and active and the
* usage count is incremented. If the driver supports runtime PM,
@@ -298,6 +302,8 @@ static long local_pci_probe(void *_ddi)
pm_runtime_set_suspended(dev);
pm_runtime_put_noidle(dev);
}
+ if (parent)
+ pm_runtime_put(parent);
return rc;
}