[git] batman-adv branch, linux, updated. 5ff6d9f73e1a8751740bc537732d05a99dfbc01b - commits - lists.open-mesh.org

9 Nov 2009

The following commit has been merged in the linux branch:
commit e13cdbd71fe12c4e191b737c4a3dbfdb4b2de03b
Author: Rafael J. Wysocki rjw@sisk.pl
Date:   Mon Oct 5 00:48:40 2009 +0200
PCI PM: Read device power state from register after updating it
After attempting to change the power state of a PCI device
    pci_raw_set_power_state() doesn't check if the value it wrote into
    the device's PCI_PM_CTRL register has been stored in there, but
    unconditionally modifies the device's current_state field to reflect
    the change.  This may cause problems to happen if the power state of
    the device hasn't been changed in fact, because it will make the PCI
    PM core make a wrong assumption.
To prevent such situations from happening modify
    pci_raw_set_power_state() so that it reads the device's PCI_PM_CTRL
    register after writing into it and uses the value read from the
    register to update the device's current_state field.  Also make it
    print a message saying that the device refused to change its power
    state as requested (returning an error code in such cases would cause
    suspend regressions to appear on some systems, where device drivers'
    suspend routines return error codes if pci_set_power_state() fails).
Reviewed-by: Alex Chiang achiang@hp.com
    Signed-off-by: Rafael J. Wysocki rjw@sisk.pl
    Signed-off-by: Jesse Barnes jbarnes@virtuousgeek.org

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 6edecff..6e1da5a 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -513,7 +513,11 @@ static int pci_raw_set_power_state(struct pci_dev *dev, pci_power_t state)
    else if (state == PCI_D2 || dev->current_state == PCI_D2)
    	udelay(PCI_PM_D2_DELAY);
-	dev->current_state = state;
+	pci_read_config_word(dev, dev->pm_cap + PCI_PM_CTRL, &pmcsr);
+	dev->current_state = (pmcsr & PCI_PM_CTRL_STATE_MASK);
+	if (dev->current_state != state && printk_ratelimit())
+		dev_info(&dev->dev, "Refused to change power state, "
+			"currently in D%d\n", dev->current_state);
/* According to section 5.4.1 of the "PCI BUS POWER MANAGEMENT
     * INTERFACE SPECIFICATION, REV. 1.2", a device transitioning
-- 
batman-adv

    