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PCI: reset pci device state to unknown state for resume

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Considering below scenario:
1.Unload a PCI device's driver, the device ->current remains in PCI_D0.
2.Do suspend/resume circle. After that, BIOS puts the device to D3.
3.Reload the device driver. The calling pci_set_power_state in the
driver can't change the state to D0, as set_power_state thinks the
device is already in D0.

A bug is reported at http://bugzilla.kernel.org/show_bug.cgi?id=6024
Pat attached a patch at
http://marc.theaimsgroup.com/?l=linux-pci&m=114049761428561&w=2 for this
issue, but it's lost. As pci_set_power_state can handle D3 -> D0
correctly (restore config space), I simplified Patrick's patch.

Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Cc: Patrick Mochel <mochel@digitalimplant.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Shaohua Li 2006-10-20 14:45:32 -07:00 committed by Greg Kroah-Hartman
parent 3095fc0c97
commit 2449e06a56
1 changed files with 13 additions and 0 deletions
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13
drivers/pci/pci-driver.c
View file

@ -264,6 +264,13 @@ static int pci_device_remove(struct device * dev)
pci_dev->driver = NULL;
}
/*
* If the device is still on, set the power state as "unknown",
* since it might change by the next time we load the driver.
*/
if (pci_dev->current_state == PCI_D0)
pci_dev->current_state = PCI_UNKNOWN;
/*
* We would love to complain here if pci_dev->is_enabled is set, that
* the driver should have called pci_disable_device(), but the
@ -288,6 +295,12 @@ static int pci_device_suspend(struct device * dev, pm_message_t state)
suspend_report_result(drv->suspend, i);
} else {
pci_save_state(pci_dev);
/*
* mark its power state as "unknown", since we don't know if
* e.g. the BIOS will change its device state when we suspend.
*/
if (pci_dev->current_state == PCI_D0)
pci_dev->current_state = PCI_UNKNOWN;
}
return i;
}