On Fri, Jun 28, 2024 at 6:27 PM Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote: > > > I assume that to take advantage of remote wake up, the device needs to > > first of all set the USB_DEVICE_REMOTE_WAKEUP bit in bmAttributes. > > That bit gets set when the host tells the gadget to enable remote > wakeup. And generally the UDC driver handles this, not the gadget > driver. Right, sorry, I meant the USB_CONFIG_ATT_WAKEUP bit. > > But then, is the wake up supposed to be initiated through the gadget > > driver or through the UDC sysfs files as the ones that Darrion > > mentioned? > > The wakeup request is initiated by the gadget driver calling > usb_gadget_wakeup(). > > > For the former case, I assume that adding a new ioctl to Raw Gadget > > that calls usb_gadget_wakeup() would be a way to support this? > > Yes. > > > AFAICS, only the g_zero gadget driver calls usb_gadget_wakeup(). Do > > the other gadget drivers just have no support for remote wake up? > > Grep shows that function/u_ether.c also calls usb_gadget_wakeup(). I > don't know about most of the gadget drivers. The f_mass_storage driver > has no need for remote wakeup, for example, and the same is probably > true for a lot of the others. You'd think that the f_hid function would > support remote wakeup, but maybe nobody ever implemented it. Understood, thank you! Darrion, you can try adding a new Raw Gadget ioctl that calls usb_gadget_wakeup() and see if that works for you. This shouldn't be hard: just add another handler to raw_ioctl(). And you probably also still need to set the USB_CONFIG_ATT_WAKEUP bit in the USB config descriptor in the Raw Gadget keyboard example. For a proper remote wake up support, I think we would also need another two ioctls: one for checking whether the UDC supports remote wake up and one for checking whether the device is suspended (the former can be combined with reporting other UDC capabilities: https://github.com/xairy/raw-gadget/issues/41).
