From b8f3601daae5c8b50ca6f7da74bb150f2eef9453 Mon Sep 17 00:00:00 2001
From: Pedroa Liu <pedroa.liu@insyde.com>
Date: Mon, 16 May 2016 20:48:41 +0800
Subject: [PATCH] ShellPkg: Fix the incorrect behavior when pressing 'shift'
 key.

If 'ReadKeyStroke' function return EFI_NOT_READY then skip it.
If the return value is EFI_DEVICE_ERROR clean the currentString buffer.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Pedroa Liu <pedroa.liu@insyde.com>
Reviewed-by: Qiu Shumin <shumin.qiu@intel.com>
---
 ShellPkg/Application/Shell/FileHandleWrappers.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/ShellPkg/Application/Shell/FileHandleWrappers.c b/ShellPkg/Application/Shell/FileHandleWrappers.c
index 0e5efe3025..f64915d9ed 100644
--- a/ShellPkg/Application/Shell/FileHandleWrappers.c
+++ b/ShellPkg/Application/Shell/FileHandleWrappers.c
@@ -422,6 +422,12 @@ FileInterfaceStdInRead(
     gBS->WaitForEvent (1, &gST->ConIn->WaitForKey, &EventIndex);
     Status = gST->ConIn->ReadKeyStroke (gST->ConIn, &Key);
     if (EFI_ERROR (Status)) {
+
+      if (Status == EFI_NOT_READY)
+        continue;
+
+      ZeroMem (CurrentString, MaxStr * sizeof(CHAR16));
+      StringLen = 0;
       break;
     }