From 04ad241e2081312be62a9f299311949e85ed725c Mon Sep 17 00:00:00 2001
From: Olivier Martin <olivier.martin@arm.com>
Date: Tue, 19 Aug 2014 13:35:14 +0000
Subject: ArmPkg/BdsLib: Prevent a hang in BdsConnectDevicePath() when a
 sub-device path is not found

Some device paths were making BdsConnectDevicePath() hang.
To prevent these hangs we check if the handle returned by
gBS->LocateDevicePath() is the same after each iteration.

An example of a device path that hangs:
PciRoot(0x0)/Pci(0x1,0x0)/USB(0x0,0x0)/USB(0x3,0x0)/HD(...)
The connect controller function manages to find PciRoot()/Pci(0x1,0x0)
but the USB driver does not produce USB(0x0,0x0)/USB(0x3,0x0) and
returns EFI_SUCCESS on its initialization.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Olivier Martin <olivier.martin@arm.com>



git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@15835 6f19259b-4bc3-4df7-8a09-765794883524
---
 ArmPkg/Library/BdsLib/BdsFilePath.c | 29 +++++++++++++++++++++--------
 ArmPkg/Library/BdsLib/BdsHelper.c   |  1 -
 ArmPkg/Library/BdsLib/BdsInternal.h |  1 +
 3 files changed, 22 insertions(+), 9 deletions(-)

(limited to 'ArmPkg')

diff --git a/ArmPkg/Library/BdsLib/BdsFilePath.c b/ArmPkg/Library/BdsLib/BdsFilePath.c
index 710821cd05..f26ba39ddb 100644
--- a/ArmPkg/Library/BdsLib/BdsFilePath.c
+++ b/ArmPkg/Library/BdsLib/BdsFilePath.c
@@ -311,27 +311,40 @@ BdsConnectAndUpdateDevicePath (
   EFI_DEVICE_PATH*            Remaining;
   EFI_DEVICE_PATH*            NewDevicePath;
   EFI_STATUS                  Status;
+  EFI_HANDLE                  PreviousHandle;
 
   if ((DevicePath == NULL) || (*DevicePath == NULL) || (Handle == NULL)) {
     return EFI_INVALID_PARAMETER;
   }
 
+  PreviousHandle = NULL;
   do {
     Remaining = *DevicePath;
+
     // The LocateDevicePath() function locates all devices on DevicePath that support Protocol and returns
     // the handle to the device that is closest to DevicePath. On output, the device path pointer is modified
     // to point to the remaining part of the device path
     Status = gBS->LocateDevicePath (&gEfiDevicePathProtocolGuid, &Remaining, Handle);
+
     if (!EFI_ERROR (Status)) {
-      // Recursive = FALSE: We do not want to start all the device tree
-      Status = gBS->ConnectController (*Handle, NULL, Remaining, FALSE);
-    }
+      if (*Handle == PreviousHandle) {
+        //
+        // If no forward progress is made try invoking the Dispatcher.
+        // A new FV may have been added to the system and new drivers
+        // may now be found.
+        // Status == EFI_SUCCESS means a driver was dispatched
+        // Status == EFI_NOT_FOUND means no new drivers were dispatched
+        //
+        Status = gDS->Dispatch ();
+      }
 
-    /*// We need to check if RemainingDevicePath does not point on the last node. Otherwise, calling
-    // NextDevicePathNode () will return an undetermined Device Path Node
-    if (!IsDevicePathEnd (RemainingDevicePath)) {
-      RemainingDevicePath = NextDevicePathNode (RemainingDevicePath);
-    }*/
+      if (!EFI_ERROR (Status)) {
+        PreviousHandle = *Handle;
+
+        // Recursive = FALSE: We do not want to start the whole device tree
+        Status = gBS->ConnectController (*Handle, NULL, Remaining, FALSE);
+      }
+    }
   } while (!EFI_ERROR (Status) && !IsDevicePathEnd (Remaining));
 
   if (!EFI_ERROR (Status)) {
diff --git a/ArmPkg/Library/BdsLib/BdsHelper.c b/ArmPkg/Library/BdsLib/BdsHelper.c
index 1d4aa35728..7f83c2be8a 100644
--- a/ArmPkg/Library/BdsLib/BdsHelper.c
+++ b/ArmPkg/Library/BdsLib/BdsHelper.c
@@ -14,7 +14,6 @@
 
 #include "BdsInternal.h"
 
-#include <Library/DxeServicesTableLib.h>
 #include <Library/HobLib.h>
 #include <Library/TimerLib.h>
 #include <Library/PrintLib.h>
diff --git a/ArmPkg/Library/BdsLib/BdsInternal.h b/ArmPkg/Library/BdsLib/BdsInternal.h
index 88117016ce..9b5d3a4ff6 100644
--- a/ArmPkg/Library/BdsLib/BdsInternal.h
+++ b/ArmPkg/Library/BdsLib/BdsInternal.h
@@ -19,6 +19,7 @@
 #include <Library/ArmLib.h>
 #include <Library/BaseLib.h>
 #include <Library/BaseMemoryLib.h>
+#include <Library/DxeServicesTableLib.h>
 #include <Library/HobLib.h>
 #include <Library/UefiBootServicesTableLib.h>
 #include <Library/UefiLib.h>
-- 
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