From d2dab6357293882ccfed82241118e90ded8191e1 Mon Sep 17 00:00:00 2001
From: Stefan Rueger <stefan.rueger@urclocks.com>
Date: Wed, 17 Jun 2026 22:34:05 +0100
Subject: [PATCH] Guard max packet size from too big values

---
 src/usb_hidapi.c | 2 +-
 src/usb_libusb.c | 4 ++++
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/usb_hidapi.c b/src/usb_hidapi.c
index d3a019af..beda975b 100644
--- a/src/usb_hidapi.c
+++ b/src/usb_hidapi.c
@@ -213,7 +213,7 @@ static int usbhid_open(const char *port, union pinfo pinfo, union filedescriptor
     }
   }
   if(fd->usb.max_xfer > USBDEV_MAX_XFER_3) {
-    pmsg_error("unexpected max size %d, reducing to %d\n", fd->usb.max_xfer, USBDEV_MAX_XFER_3);
+    pmsg_error("reducing too big max packet size %d to %d\n", fd->usb.max_xfer, USBDEV_MAX_XFER_3);
     fd->usb.max_xfer = USBDEV_MAX_XFER_3;
   }
 
diff --git a/src/usb_libusb.c b/src/usb_libusb.c
index 05ca8406..70c58fd8 100644
--- a/src/usb_libusb.c
+++ b/src/usb_libusb.c
@@ -213,6 +213,10 @@ static int usbdev_open(const char *port, union pinfo pinfo, union filedescriptor
               }
             }
           }
+          if(fd->usb.max_xfer > USBDEV_MAX_XFER_3) {
+            pmsg_error("reducing too big max packet size %d to %d\n", fd->usb.max_xfer, USBDEV_MAX_XFER_3);
+           fd->usb.max_xfer = USBDEV_MAX_XFER_3;
+          }
           if(usehid && usb_control_msg(udev, 0x21, 0x0a /* SET_IDLE */ , 0, 0, NULL, 0, 100) < 0)
             pmsg_warning("SET_IDLE failed\n");
           return 0;