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(-)
--
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