From e117c894fdf1896fea5d37057832fed58d48b6ee Mon Sep 17 00:00:00 2001
From: Michael Brown <mcb30@ipxe.org>
Date: Wed, 11 May 2016 22:50:09 +0100
Subject: [PATCH] EmbeddedPkg/Lan9118Dxe: Do not return uninitialised TxBuff

Conform to the specification for GetStatus(), which states that "if
there are no transmit buffers to recycle and TxBuf is not NULL, *TxBuf
will be set to NULL".

Cc: Leif Lindholm <leif.lindholm@linaro.org>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 EmbeddedPkg/Drivers/Lan9118Dxe/Lan9118Dxe.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/EmbeddedPkg/Drivers/Lan9118Dxe/Lan9118Dxe.c b/EmbeddedPkg/Drivers/Lan9118Dxe/Lan9118Dxe.c
index 8af23df394..aabaf604f6 100644
--- a/EmbeddedPkg/Drivers/Lan9118Dxe/Lan9118Dxe.c
+++ b/EmbeddedPkg/Drivers/Lan9118Dxe/Lan9118Dxe.c
@@ -1055,6 +1055,8 @@ SnpGetStatus (
       LanDriver->Stats.TxTotalFrames += 1;
       *TxBuff = LanDriver->TxRing[PacketTag % LAN9118_TX_RING_NUM_ENTRIES];
     }
+  } else if (TxBuff != NULL) {
+    *TxBuff = NULL;
   }
 
   // Check for a TX Error interrupt