On Wed, Mar 6, 2013 at 10:51 AM, Ming Lei <[email protected]> wrote: > On Wed, Mar 6, 2013 at 12:08 AM, Bjørn Mork <[email protected]> wrote: >> Ming Lei <[email protected]> writes: >> >> I am starting to wonder why the USB core has combined system suspend and >> runtime suspend if we are going to end up with every driver testing >> PMSG_IS_AUTO(message) and selecting a completely different code path. >> >> You are right that we will end up with problems if usbnet_resume is >> called for a device usbnet hasn't suspended. But I'd still claim that >> is a bug in the USB core, which is the one that decided to ignore the >> suspend error and still call resume. >> >> I guess proper error handling here require the USB core to see the >> interface driver as dead if it fails to suspend on system suspend, and >> do forced rebinding on resume. > > The idea should be fine, but may cause regression of user space, suppose > one device with suspend failure can be across suspend-resume cycle and > work well before, but it is no longer with your forced rebinding.
Give the potential cost(user space regression) of doing rebind, I think it is better to try to recover the device in resume() first, then consider rebinding as the last straw. In fact, I am also wondering if resume() can't recover one device but probe() can, maybe we can always let resume() recover the device which experienced suspend failure. I remember that some guys went against rebinding during system sleep before in the firmware loading discussion. Thanks, -- Ming Lei -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
