Check for no usb device in usb_ftdi_cts

usbutils.c

@@ -2027,8 +2027,13 @@ int _usb_read(struct cgpu_info *cgpu, int ep, char *buf, size_t bufsiz, int *pro
 	unsigned char usbbuf[USB_MAX_READ+4], *ptr;
 	size_t usbbufread;
 
-	if (unlikely(!usbdev))
+	if (cgpu->usbinfo.nodev) {
+		*buf = '\0';
+		*processed = 0;
+		USB_REJECT(cgpu, MODE_BULK_READ);
+
 		return LIBUSB_ERROR_NO_DEVICE;
+	}
 
 	ftdi = (usbdev->usb_type == USB_TYPE_FTDI);
 
@@ -2037,14 +2042,6 @@ int _usb_read(struct cgpu_info *cgpu, int ep, char *buf, size_t bufsiz, int *pro
 	if (bufsiz > USB_MAX_READ)
 		quit(1, "%s USB read request %d too large (max=%d)", cgpu->drv->name, bufsiz, USB_MAX_READ);
 
-	if (cgpu->usbinfo.nodev) {
-		*buf = '\0';
-		*processed = 0;
-		USB_REJECT(cgpu, MODE_BULK_READ);
-
-		return LIBUSB_ERROR_NO_DEVICE;
-	}
-
 	if (timeout == DEVTIMEOUT)
 		timeout = usbdev->found->timeout;
 
@@ -2204,6 +2201,11 @@ int usb_ftdi_cts(struct cgpu_info *cgpu)
 	struct cg_usb_device *usbdev = cgpu->usbdev;
 	unsigned char buf[2], ret;
 
+	/* We return true in case drivers are waiting indefinitely to try and
+	 * write to something that's not there. */
+	if (cgpu->usbinfo.nodev)
+		return true;
+
 	libusb_control_transfer(usbdev->handle, (uint8_t)FTDI_TYPE_IN,
 				(uint8_t)5, (uint16_t)0, (uint16_t)0, buf, 2,
 				DEVTIMEOUT);