1 files changed, 11 insertions, 0 deletions

diff --git a/Documentation/serial/driver b/Documentation/serial/driver
index 88ad615dd338..77ba0afbe4db 100644
--- a/Documentation/serial/driver
+++ b/Documentation/serial/driver
@@ -186,6 +186,17 @@ hardware.
         Locking: port_sem taken.
         Interrupts: caller dependent.
 
+  flush_buffer(port)
+        Flush any write buffers, reset any DMA state and stop any
+        ongoing DMA transfers.
+
+        This will be called whenever the port->info->xmit circular
+        buffer is cleared.
+
+        Locking: port->lock taken.
+        Interrupts: locally disabled.
+        This call must not sleep
+
   set_termios(port,termios,oldtermios)
         Change the port parameters, including word length, parity, stop
         bits.  Update read_status_mask and ignore_status_mask to indicate