Re: [PATCH] usb: dwc3: gadget: Inform system of suspended state

[Thinh Nguyen <Thinh.Nguyen@synopsys.com>]

On Thu, Jun 13, 2024, Mike Looijmans wrote:
> > 
> > Wait, I thought the host initiated the usb suspend. Did you trigger usb
> > suspend by putting the host in suspend? Or does the suspend event only
> > come when you perform a disconnect?
> 
> All I do is unplug the cable. The host (PC running Ubuntu 22) doesn't eject
> or suspend or anything like that.
> 

This is a very typical connect/disconnect flow. I'm surprised that it's
not caught on your platform before. What's the compatible string for
your platform?

> 
> > 
> > Can you confirm if the suspend event was there before you disconnect the
> > device?
> 
> Disconnecting the cable is what leads to the "suspend" event.
> 

Can you try this:

It's a simple workaround, but may not catch the issue while operating in
Fullspeed.

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 89fc690fdf34..894ca1044281 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -4339,6 +4339,18 @@ static void dwc3_gadget_suspend_interrupt(struct dwc3 *dwc,
 {
 	enum dwc3_link_state next = evtinfo & DWC3_LINK_STATE_MASK;
 
+	if (next == DWC3_LINK_STATE_U3) {
+		u8 speed;
+		u32 reg;
+
+		reg = dwc3_readl(dwc->regs, DWC3_DSTS);
+		speed = reg & DWC3_DSTS_CONNECTSPD;
+		if (dwc->speed != speed) {
+			dwc3_gadget_disconnect_interrupt(dwc);
+			return;
+		}
+	}
+
 	if (!dwc->suspended && next == DWC3_LINK_STATE_U3) {
 		dwc->suspended = true;
 		dwc3_suspend_gadget(dwc);


Otherwise, there's no other SW workaround that I can think of.

BR,
Thinh