When a PCI bridge is runtime resumed from D3cold the underlying bus is
walked and the attached devices are runtime resumed as well. However, in
addition to that we also generate a wakeup event for these devices even
though this actually is not a real wakeup event coming from the
hardware.
Normally this does not cause problems but when combined with
/sys/power/wakeup_count like using the steps below:
# count=$(cat /sys/power/wakeup_count)
# echo $count > /sys/power/wakeup_count
# echo mem > /sys/power/state
The system suspend cycle might get aborted at this point if a PCI bridge
that was runtime suspended (D3cold) was runtime resumed for any reason.
The runtime resume calls pci_wakeup_bus() and that generates wakeup
event increasing wakeup_count.
Since this is not a real wakeup event we can prevent the above from
happening by removing the call to pci_wakeup_event() in
pci_wakeup_bus(). While there rename pci_wakeup_bus() to
pci_resume_bus() to better reflect what it does.
Reported-by: Utkarsh Patel <utkarsh.h.patel@xxxxxxxxx>
Signed-off-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
---
drivers/gpu/vga/vga_switcheroo.c | 2 +-
drivers/pci/pci.c | 16 +++++-----------
include/linux/pci.h | 2 +-
3 files changed, 7 insertions(+), 13 deletions(-)
diff --git a/drivers/gpu/vga/vga_switcheroo.c b/drivers/gpu/vga/vga_switcheroo.c
index 087304b1a5d7..8843b078ad4e 100644
--- a/drivers/gpu/vga/vga_switcheroo.c
+++ b/drivers/gpu/vga/vga_switcheroo.c
@@ -1039,7 +1039,7 @@ static int vga_switcheroo_runtime_resume(struct device *dev)
mutex_lock(&vgasr_mutex);
vga_switcheroo_power_switch(pdev, VGA_SWITCHEROO_ON);
mutex_unlock(&vgasr_mutex);
- pci_wakeup_bus(pdev->bus);
+ pci_resume_bus(pdev->bus);
ret = dev->bus->pm->runtime_resume(dev);
if (ret)
return ret;
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 6d4d5a2f923d..b25dfa63eeb9 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1174,26 +1174,20 @@ int pci_platform_power_transition(struct pci_dev *dev, pci_power_t state)
}
EXPORT_SYMBOL_GPL(pci_platform_power_transition);
-/**
- * pci_wakeup - Wake up a PCI device
- * @pci_dev: Device to handle.
- * @ign: ignored parameter
- */
-static int pci_wakeup(struct pci_dev *pci_dev, void *ign)
+static int pci_resume_one(struct pci_dev *pci_dev, void *ign)
{
- pci_wakeup_event(pci_dev);
pm_request_resume(&pci_dev->dev);
return 0;
}
/**
- * pci_wakeup_bus - Walk given bus and wake up devices on it
+ * pci_resume_bus - Walk given bus and runtime resume devices on it
* @bus: Top bus of the subtree to walk.
*/
-void pci_wakeup_bus(struct pci_bus *bus)
+void pci_resume_bus(struct pci_bus *bus)
{
if (bus)
- pci_walk_bus(bus, pci_wakeup, NULL);
+ pci_walk_bus(bus, pci_resume_one, NULL);
}
static int pci_dev_wait(struct pci_dev *dev, char *reset_type, int timeout)
@@ -1256,7 +1250,7 @@ int pci_power_up(struct pci_dev *dev)
* may be powered on into D0uninitialized state, resume them to
* give them a chance to suspend again
*/
- pci_wakeup_bus(dev->subordinate);
+ pci_resume_bus(dev->subordinate);
}
return pci_raw_set_power_state(dev, PCI_D0);
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 22207a79762c..9256ef2e4327 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1271,7 +1271,7 @@ bool pci_dev_run_wake(struct pci_dev *dev);
void pci_d3cold_enable(struct pci_dev *dev);
void pci_d3cold_disable(struct pci_dev *dev);
bool pcie_relaxed_ordering_enabled(struct pci_dev *dev);
-void pci_wakeup_bus(struct pci_bus *bus);
+void pci_resume_bus(struct pci_bus *bus);
void pci_bus_set_current_state(struct pci_bus *bus, pci_power_t state);
/* For use by arch with custom probe code */
--
2.28.0
