From c723bbd6be642ab939fa183fb065fc4928069b3c Mon Sep 17 00:00:00 2001
From: Dean Lee <deanlee3@gmail.com>
Date: Fri, 29 Jan 2021 20:00:49 +0800
Subject: [PATCH] Panda: add check for connected in usb_read (#19957)

---
 selfdrive/boardd/panda.cc | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/selfdrive/boardd/panda.cc b/selfdrive/boardd/panda.cc
index 0bc72cff63..8f9525fb61 100644
--- a/selfdrive/boardd/panda.cc
+++ b/selfdrive/boardd/panda.cc
@@ -118,6 +118,10 @@ int Panda::usb_read(uint8_t bRequest, uint16_t wValue, uint16_t wIndex, unsigned
   int err;
   const uint8_t bmRequestType = LIBUSB_ENDPOINT_IN | LIBUSB_REQUEST_TYPE_VENDOR | LIBUSB_RECIPIENT_DEVICE;
 
+  if (!connected){
+    return LIBUSB_ERROR_NO_DEVICE;
+  }
+
   std::lock_guard lk(usb_lock);
   do {
     err = libusb_control_transfer(dev_handle, bmRequestType, bRequest, wValue, wIndex, data, wLength, timeout);