[PATCH] usb: dwc3: gadget: Fix spurious suspend event during HS link training

[Saranya R <saranya.r@oss.qualcomm.com>]

During HS link training, a spurious DWC3_DEVICE_EVENT_SUSPEND carrying
link state U3 is fired before CONNECT_DONE completes enumeration. At
this point gadget->speed is USB_SPEED_UNKNOWN since CONNECT_DONE has
not yet run. Calling dwc3_gadget_suspend_interrupt() here triggers an
unwanted composite_suspend, causing the charger framework to drop
current to 2mA and then ramp back to 500mA on every USB connection.

Fix this by skipping suspend event processing when gadget->speed is
USB_SPEED_UNKNOWN. This precisely targets the pre-enumeration window
without affecting genuine suspend events: a real suspend at ADDRESS
state (required for BC1.2 compliance) only arrives after CONNECT_DONE
sets gadget->speed to the negotiated speed, so gadget->speed is no
longer UNKNOWN at that point.

Fixes: 4decf4060ecf ("usb: dwc3: gadget: Change condition for processing suspend event")
Signed-off-by: Saranya R <saranya.r@oss.qualcomm.com>
---
 drivers/usb/dwc3/gadget.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index bfb20c3ac392..7d0d24b6c04d 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -4465,8 +4465,18 @@ static void dwc3_gadget_interrupt(struct dwc3 *dwc,
 		break;
 	case DWC3_DEVICE_EVENT_SUSPEND:
 		/* It changed to be suspend event for version 2.30a and above */
-		if (!DWC3_VER_IS_PRIOR(DWC3, 230A))
-			dwc3_gadget_suspend_interrupt(dwc, event->event_info);
+		if (!DWC3_VER_IS_PRIOR(DWC3, 230A)) {
+			/*
+			 * A spurious U3 suspend event is fired during HS link
+			 * training before CONNECT_DONE sets the gadget speed.
+			 * Ignore it at that point to avoid triggering an unwanted
+			 * composite_suspend. A genuine suspend at ADDRESS state
+			 * (required for BC1.2 compliance) only arrives after
+			 * CONNECT_DONE, so gadget->speed is no longer UNKNOWN then.
+			 */
+			if (dwc->gadget->speed != USB_SPEED_UNKNOWN)
+				dwc3_gadget_suspend_interrupt(dwc, event->event_info);
+		}
 		break;
 	case DWC3_DEVICE_EVENT_SOF:
 	case DWC3_DEVICE_EVENT_ERRATIC_ERROR:
-- 
2.34.1