On 12/13/2023 12:31, Rafael J. Wysocki wrote:
On Wed, Dec 13, 2023 at 7:27 PM Mario Limonciello
<mario.limonciello@xxxxxxx> wrote:
When the system is going to S5 resuming devices is unnecessary at
best and may cause problems for power consumption at S5 at worst.
Check the target `system_state` in the pci driver shutdown() callback
and skip the runtime resume step if the system is being powered off.
Cc: mpearson-lenovo@xxxxxxxxx
Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxx>
---
drivers/pci/pci-driver.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
index 51ec9e7e784f..5a6f7a786952 100644
--- a/drivers/pci/pci-driver.c
+++ b/drivers/pci/pci-driver.c
@@ -507,7 +507,9 @@ static void pci_device_shutdown(struct device *dev)
struct pci_dev *pci_dev = to_pci_dev(dev);
struct pci_driver *drv = pci_dev->driver;
- pm_runtime_resume(dev);
+ /* If system will go to S5, don't wake up PCI devices for shutdown */
+ if (system_state != SYSTEM_POWER_OFF)
+ pm_runtime_resume(dev);
What's the guarantee that the driver's shutdown callback will not
access MMIO regions of a runtime-suspended device?
This is something that may need to be audited.
I have an expectation that drivers will runtime resume a device before
they try to access it.
if (drv && drv->shutdown)
drv->shutdown(pci_dev);
--
