Ignore USB role switches if dwc3-apple is already in the desired state. The USB-C port controller on M2 and M1/M2 Pro/Max/Ultra devices issues additional interrupts which result in USB role switches to the already active role. Ignore these USB role switches to ensure the USB-C port controller and dwc3-apple are always in a consistent state. This matches the behaviour in __dwc3_set_mode() in core.c. Fixes detecting USB 2.0 and 3.x devices on the affected systems. The reset caused by the additional role switch appears to leave the USB devices in a state which prevents detection when the phy and dwc3 is brought back up again.
Fixes: 0ec946d32ef7 ("usb: dwc3: Add Apple Silicon DWC3 glue layer driver") Cc: stable@vger.kernel.org Signed-off-by: Janne Grunau j@jannau.net --- drivers/usb/dwc3/dwc3-apple.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+)
diff --git a/drivers/usb/dwc3/dwc3-apple.c b/drivers/usb/dwc3/dwc3-apple.c index cc47cad232e397ac4498b09165dfdb5bd215ded7..35eadd1fa08049829ba40651a96eb122ed55460f 100644 --- a/drivers/usb/dwc3/dwc3-apple.c +++ b/drivers/usb/dwc3/dwc3-apple.c @@ -339,6 +339,22 @@ static int dwc3_usb_role_switch_set(struct usb_role_switch *sw, enum usb_role ro
guard(mutex)(&appledwc->lock);
+ /* + * Skip role switches if appledwc is already in the desired state. The + * USB-C port controller on M2 and M1/M2 Pro/Max/Ultra devices issues + * additional interrupts which results in usb_role_switch_set_role() + * calls with the current role. + * Ignore those calls here to ensure the USB-C port controller and + * appledwc are in a consistent state. + * This matches the behaviour in __dwc3_set_mode(). + * Do no handle USB_ROLE_NONE for DWC3_APPLE_NO_CABLE and + * DWC3_APPLE_PROBE_PENDING since that is no-op anyway. + */ + if (appledwc->state == DWC3_APPLE_HOST && role == USB_ROLE_HOST) + return 0; + if (appledwc->state == DWC3_APPLE_DEVICE && role == USB_ROLE_DEVICE) + return 0; + /* * We need to tear all of dwc3 down and re-initialize it every time a cable is * connected or disconnected or when the mode changes. See the documentation for enum
--- base-commit: 8f0b4cce4481fb22653697cced8d0d04027cb1e8 change-id: 20260109-apple-dwc3-role-switch-1b684f73860c
Best regards,