[PATCH 1/1] OvmfPkg/PlatformBootManagerLib: Don't update progress if Pcd is 0

["Pete Batard" <pete@akeo.ie>]

BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=2266

Independently of how we decide to address other aspects of the regression
introduced with commit 2de1f611be06ded3a59726a4052a9039be7d459b, it doesn't
make much sense to call for a progress update if PcdPlatformBootTimeOut is
zero.

PcdPlatformBootTimeOut 0, which is the cause of the bug (division by zero)
should be considered to indicate that a platform is not interested in
displaying a progress report, so we alter PlatformBootManagerWaitCallback
to behave that way.

We also change one variable name to make the code more explicit.

Signed-off-by: Pete Batard <pete@akeo.ie>
---
 OvmfPkg/Library/PlatformBootManagerLib/BdsPlatform.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/OvmfPkg/Library/PlatformBootManagerLib/BdsPlatform.c b/OvmfPkg/Library/PlatformBootManagerLib/BdsPlatform.c
index 70df6b841acc..352163436e10 100644
--- a/OvmfPkg/Library/PlatformBootManagerLib/BdsPlatform.c
+++ b/OvmfPkg/Library/PlatformBootManagerLib/BdsPlatform.c
@@ -1631,9 +1631,16 @@ PlatformBootManagerWaitCallback (
 {
   EFI_GRAPHICS_OUTPUT_BLT_PIXEL_UNION Black;
   EFI_GRAPHICS_OUTPUT_BLT_PIXEL_UNION White;
-  UINT16                              Timeout;
+  UINT16                              TimeoutInitial;
 
-  Timeout = PcdGet16 (PcdPlatformBootTimeOut);
+  TimeoutInitial = PcdGet16 (PcdPlatformBootTimeOut);
+
+  // If PcdPlatformBootTimeOut is set to zero, then we consider
+  // that no progress update should be enacted (since we'd only
+  // ever display a one-shot progress of either 0% or 100%).
+  if (TimeoutInitial == 0) {
+    return;
+  }
 
   Black.Raw = 0x00000000;
   White.Raw = 0x00FFFFFF;
@@ -1643,7 +1650,7 @@ PlatformBootManagerWaitCallback (
     Black.Pixel,
     L"Start boot option",
     White.Pixel,
-    (Timeout - TimeoutRemain) * 100 / Timeout,
+    (TimeoutInitial - TimeoutRemain) * 100 / TimeoutInitial,
     0
     );
 }
-- 
2.21.0.windows.1