diff --git a/lib/libusb/libusb.h b/lib/libusb/libusb.h
--- a/lib/libusb/libusb.h
+++ b/lib/libusb/libusb.h
@@ -513,6 +513,9 @@
 int 	libusb_attach_kernel_driver(libusb_device_handle * devh, int interface);
 int	libusb_set_auto_detach_kernel_driver(libusb_device_handle *dev, int enable);
 int	libusb_set_interface_alt_setting(libusb_device_handle * devh, int interface_number, int alternate_setting);
+unsigned char *libusb_dev_mem_alloc(libusb_device_handle *devh);
+int	libusb_dev_mem_free(libusb_device_handle *devh, unsigned char *buffer,
+    size_t size);
 
 /* USB Descriptors */
 
diff --git a/lib/libusb/libusb.3 b/lib/libusb/libusb.3
--- a/lib/libusb/libusb.3
+++ b/lib/libusb/libusb.3
@@ -22,7 +22,7 @@
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
-.Dd June 13, 2025
+.Dd July 9, 2025
 .Dt LIBUSB 3
 .Os
 .Sh NAME
@@ -366,6 +366,23 @@
 Else disabled.
 Returns 0 on success and a LIBUSB_ERROR code on
 failure.
+.Pp
+.Ft unsigned char *
+.Fn libusb_dev_mem_alloc "libusb_device_handle *devh"
+This function attempts to allocate a DMA memory block from the given
+.Fa devh
+so that we can enjoy the zero-copy transfer from kernel.
+This function is provided for compatibility and is currently unimplemented and always returns NULL.
+.Pp
+.Ft int
+.Fn libusb_dev_mem_free "libusb_device_handle *devh" "unsigned char *buffer" "size_t size"
+This function frees the DMA memory in
+.Fa devh
+from the given
+.Fa buffer
+with
+.Fa size .
+This function is unimplemented and always returns LIBUSB_ERROR_NOT_SUPPORTED.
 .Sh USB DESCRIPTORS
 .Ft int
 .Fn libusb_get_device_descriptor "libusb_device *dev" "libusb_device_descriptor *desc"
diff --git a/lib/libusb/libusb10.c b/lib/libusb/libusb10.c
--- a/lib/libusb/libusb10.c
+++ b/lib/libusb/libusb10.c
@@ -1904,3 +1904,16 @@
 
 	return (LIBUSB_ERROR_INVALID_PARAM);
 }
+
+unsigned char *
+libusb_dev_mem_alloc(libusb_device_handle *devh)
+{
+	return (NULL);
+}
+
+int
+libusb_dev_mem_free(libusb_device_handle *devh, unsigned char *buffer,
+    size_t size)
+{
+	return (LIBUSB_ERROR_NOT_SUPPORTED);
+}