On Tue, May 28, 2013 at 02:41:18PM -0700, Julius Werner wrote: > The policy we want to achieve is to disable runtime PM iff there is a > device connected that doesn't have persist_enabled or a reset_resume() > handler and whose parent/root hub resets on resume, right? Makes sense. However, not all distros may want that policy, so there should be a way to change that policy via sysfs. Some distros may choose to take the power savings over having a particular USB device work, especially in the server market. Don, Oliver, what do you think of this patch: http://marc.info/?l=linux-usb&m=136941922715772&w=2 Julius is proposing to limit the scope of the patch a bit, but the impact will still be that TI hosts will be active more often than not. > So couldn't > we remove the HCD-specific XHCI_RESET_ON_RESUME and set the (existing) > generic USB_QUIRK_RESET_RESUME on the root hub instead? Then we could > handle all of this in the USB core (during device initialization and > when changing persist_enabled through sysfs) by just checking for > udev->reset_resume on all parent hubs of the device in question (and > use pm_runtime_get/put() on said device to prevent its parents from > suspending as appropriate). Alan, what happens if we set USB_QUIRK_RESET_RESUME on the roothub? I don't think that currently translates into the host controller's Reset register getting written, which is what I think Julius is proposing. Sarah Sharp -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
