On Thu, Jun 22, 2006 at 03:57:24PM -0400, Alan Stern wrote: > On Thu, 22 Jun 2006, Greg KH wrote: > > > > There are several possible ways to fix this. One is to add suspend and > > > resume routines to the endpoint-device driver. Another is to change the > > > code that checks for the children being suspended, to make it check only > > > for child USB devices and not child endpoints. > > > > I think it needs to check for _USB_ devices, not just any old device > > that could possibly be attached to the main USB device (as this one is.) > > What's to stop any other struct device to bind here and cause the same > > problem? > > In my upcoming patches for USB core suspend improvements, one of the > changes affects this very piece of code. Instead of looping over all > child devices in the driver-model sense, it loops over all interfaces in > the active configuration, which is all we care about right here. > > > Ok, the problem is in verify_suspended(), we are not detecting what type > > of device this is. > > > > Alan, what are you trying to check for here? What "bogus requests" were > > you seeing from sysfs that you are trying to filter out? > > I didn't write that routine, Dave Brownell did. It has been there for > ages. Sorry for the misattribution, I should have checked closer. > The "bogus requests" are attempts by the user to suspend a USB > device (by writing to /sys/devices/.../power/state) without first > suspending all its children and interfaces. > > (This can't happen when doing a global suspend because the PM core > iterates through the entire device tree. It matters only for "runtime" or > "selective" suspend.) Then why is people hitting this now? I guess no one had hooked a struct device to a struct usb_device before, only interfaces. > The two easiest ways to fix the problem are: > > Change the code to look through the interfaces in the active > configuration instead of using device_for_each_child; Or at least verify that they are looking at an interface, just blindly poking at a child device isn't very nice :( > or > > Revert your "endpoints are devices" patch until my upcoming > changes are in place. I'll work on a fix-up patch based on the first option :) thanks, greg k-h
