Hi Alan, Thanks for the details. >> tl;dr : Should device allowed to do runtime pm that have no driver go >> to D3 on their own ? > > Quick answer: See the comments at the start of local_pci_probe() in > drivers/pci/pci-driver.c. PCI devices without a kernel driver are > always left in D0, regardless of the runtime PM status. This is > because userspace may try to use the device, and the kernel wouldn't > know to take the device out of D3 when that happens. Does linux expose some way for userspace to transition the device to another power state without the need for a driver ? I looked at the docs and tried poking some of the sysfs files, but except enabling/disabling the runtme pm, I couldn't really change anything, but maybe I missed something. >> And should pci root bridge go to D3 when all the >> device on them are on D3 ? > > I don't know the answer to that. It's probably closely related to the > issue of whether PCI bridges need to have a kernel driver. OK. Do you know if there could be any adverse effect of transitioning it myself ? Basically I'm doing this when turning off the card : struct pci_dev *port_dev = pci_upstream_bridge(pdev); pci_save_state(port_dev); pci_clear_master(port_dev); pci_disable_device(port_dev); pci_set_power_state(port_dev, PCI_D3hot); And this when waking it up : pci_set_power_state(port_dev, PCI_D0); pci_restore_state(port_dev); pci_enable_device(port_dev); pci_set_master(port_dev); (I removed the return value checking to make the code more concise here). Cheers, Sylvain -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
