During the following scenario, the DWC3 runtime suspend routine is blocked as the connected flag is still true: 1. Enumerate device w/ host. 2. Gadget is unbinded - echo "" > /sys/kernel/config/usb_gadget/g1/UDC 3. Disconnect the USB cable (VBUS low) 4. No dwc3_gadget_disconnect_interrupt() seen (since controller is halted from step#1) 5. Runtime PM autosuspend fails due to "dwc->connected" being true (cleared in dwc3_gadget_disconnect_interrupt()) 6. Gadget binded - echo udc_name > /sys/kernel/config/usb_gadget/g1/UDC 7. No runtime suspend until cable is plugged in and out Technically, for device initiated disconnects, there is no active session/link with the host, so the DWC3 controller should be allowed to go into a low power state. Also, we need to now consider when re-binding the UDC, dwc3_gadget_set_speed() is executed before dwc3_gadget_pullup(), so if the DWC3 controller is suspended/disabled, while accessing the DCFG, that could result in bus timeouts, etc... Change the dwc3_gadget_set_speed() to save the speed being requested, and program it during dwc3_gadget_run_stop(), which is executed during PM runtime resume. If not, previous setting will be overridden as we execute a DWC3 controller reset during PM runtime resume. Wesley Cheng (2): usb: dwc3: gadget: Allow runtime suspend if UDC unbinded usb: dwc3: gadget: Preserve UDC max speed setting drivers/usb/dwc3/core.h | 1 + drivers/usb/dwc3/gadget.c | 114 +++++++++++++++++++++----------------- 2 files changed, 64 insertions(+), 51 deletions(-) -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
