raw_gadget: make compatible with dwc3

Not the proper solution, just a workaround. Details: https://lore.kernel.org/linux-usb/CA+fCnZcQSYy63ichdivAH5-fYvN2UMzTtZ--h=F6nK0jfVou3Q@mail.gmail.com/ Signed-off-by: Andrey Konovalov <[email protected]>
xairy · Aug 19, 2023 · dfc4ee2 · dfc4ee2
1 parent ff5ed28
commit dfc4ee2
Showing 1 changed file with 10 additions and 0 deletions.
diff --git a/raw_gadget/raw_gadget.c b/raw_gadget/raw_gadget.c
@@ -34,6 +34,9 @@ MODULE_DESCRIPTION(DRIVER_DESC);
 MODULE_AUTHOR("Andrey Konovalov");
 MODULE_LICENSE("GPL");
 
+/* Copied from include/linux/usb/composite.h. */
+#define USB_GADGET_DELAYED_STATUS 0x7fff
+
 /*----------------------------------------------------------------------*/
 
 static DEFINE_IDA(driver_id_numbers);
@@ -383,6 +386,13 @@ static int gadget_setup(struct usb_gadget *gadget,
 out_unlock:
 	spin_unlock_irqrestore(&dev->lock, flags);
 out:
+	if (ret == 0 && ctrl->wLength == 0) {
+		/*
+		 * A workaround for the dwc3 UDC driver. Prevents dwc3 from
+		 * autocompleting the status stage of the 0-length transfer.
+		 */
+		return USB_GADGET_DELAYED_STATUS;
+	}
 	return ret;
 }