1 files changed, 5 insertions, 0 deletions

diff --git a/drivers/net/usb/qmi_wwan.c b/drivers/net/usb/qmi_wwan.c
index 2a3579f67910..5a88e72090ce 100644
--- a/drivers/net/usb/qmi_wwan.c
+++ b/drivers/net/usb/qmi_wwan.c
@@ -374,6 +374,11 @@ static int qmi_wwan_suspend(struct usb_interface *intf, pm_message_t message)
         struct qmi_wwan_state *info = (void *)&dev->data;
         int ret;
 
+        /*
+         * Both usbnet_suspend() and subdriver->suspend() MUST return 0
+         * in system sleep context, otherwise, the resume callback has
+         * to recover device from previous suspend failure.
+         */
         ret = usbnet_suspend(intf, message);
         if (ret < 0)
                 goto err;