[PATCH 2/2] MdeModulePkg/PciBus: Restrict one VGA per HostBridge not Segment

[Ruiyu Ni <ruiyu.ni@intel.com>]

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=1109

Today's restriction of VGA device is to have only one VGA device
enabled per PCI segment. It's not correct because several segments
may share one IO / MMIO address space.
We should restrict to have one VGA per Host Bridge because each
Host Bridge has its only IO / MMIO address space.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Ruiyu Ni <ruiyu.ni@intel.com>
Cc: Star Zeng <star.zeng@intel.com>
---
 MdeModulePkg/Bus/Pci/PciBusDxe/PciDeviceSupport.c | 22 +++++++++++-----------
 MdeModulePkg/Bus/Pci/PciBusDxe/PciDeviceSupport.h | 10 +++++-----
 MdeModulePkg/Bus/Pci/PciBusDxe/PciIo.c            |  4 ++--
 3 files changed, 18 insertions(+), 18 deletions(-)

diff --git a/MdeModulePkg/Bus/Pci/PciBusDxe/PciDeviceSupport.c b/MdeModulePkg/Bus/Pci/PciBusDxe/PciDeviceSupport.c
index fdec0bcd53..fbcc53e41a 100644
--- a/MdeModulePkg/Bus/Pci/PciBusDxe/PciDeviceSupport.c
+++ b/MdeModulePkg/Bus/Pci/PciBusDxe/PciDeviceSupport.c
@@ -979,33 +979,33 @@ PciDeviceExisted (
 }
 
 /**
-  Get the active VGA device on the same segment.
+  Get the active VGA device on the specified Host Bridge.
 
-  @param VgaDevice    PCI IO instance for the VGA device.
+  @param HostBridgeHandle    Host Bridge handle.
 
-  @return The active VGA device on the same segment.
+  @return The active VGA device on the specified Host Bridge.
 
 **/
 PCI_IO_DEVICE *
-ActiveVGADeviceOnTheSameSegment (
-  IN PCI_IO_DEVICE        *VgaDevice
+LocateVgaDeviceOnHostBridge (
+  IN EFI_HANDLE           HostBridgeHandle
   )
 {
   LIST_ENTRY      *CurrentLink;
-  PCI_IO_DEVICE   *Temp;
+  PCI_IO_DEVICE   *PciIo;
 
   CurrentLink = mPciDevicePool.ForwardLink;
 
   while (CurrentLink != NULL && CurrentLink != &mPciDevicePool) {
 
-    Temp = PCI_IO_DEVICE_FROM_LINK (CurrentLink);
+    PciIo = PCI_IO_DEVICE_FROM_LINK (CurrentLink);
 
-    if (Temp->PciRootBridgeIo->SegmentNumber == VgaDevice->PciRootBridgeIo->SegmentNumber) {
+    if (PciIo->PciRootBridgeIo->ParentHandle== HostBridgeHandle) {
 
-      Temp = LocateVgaDevice (Temp);
+      PciIo = LocateVgaDevice (PciIo);
 
-      if (Temp != NULL) {
-        return Temp;
+      if (PciIo != NULL) {
+        return PciIo;
       }
     }
 
diff --git a/MdeModulePkg/Bus/Pci/PciBusDxe/PciDeviceSupport.h b/MdeModulePkg/Bus/Pci/PciBusDxe/PciDeviceSupport.h
index 1ec2178a21..b45d2a5d77 100644
--- a/MdeModulePkg/Bus/Pci/PciBusDxe/PciDeviceSupport.h
+++ b/MdeModulePkg/Bus/Pci/PciBusDxe/PciDeviceSupport.h
@@ -230,16 +230,16 @@ PciDeviceExisted (
   );
 
 /**
-  Get the active VGA device on the same segment.
+  Get the active VGA device on the specified Host Bridge.
 
-  @param VgaDevice    PCI IO instance for the VGA device.
+  @param HostBridgeHandle    Host Bridge handle.
 
-  @return The active VGA device on the same segment.
+  @return The active VGA device on the specified Host Bridge.
 
 **/
 PCI_IO_DEVICE *
-ActiveVGADeviceOnTheSameSegment (
-  IN PCI_IO_DEVICE        *VgaDevice
+LocateVgaDeviceOnHostBridge (
+  IN EFI_HANDLE           HostBridgeHandle
   );
 
 /**
diff --git a/MdeModulePkg/Bus/Pci/PciBusDxe/PciIo.c b/MdeModulePkg/Bus/Pci/PciBusDxe/PciIo.c
index 291578c63c..333b875ff0 100644
--- a/MdeModulePkg/Bus/Pci/PciBusDxe/PciIo.c
+++ b/MdeModulePkg/Bus/Pci/PciBusDxe/PciIo.c
@@ -1415,7 +1415,7 @@ SupportPaletteSnoopAttributes (
   //
   // Get the boot VGA on the same segement
   //
-  Temp = ActiveVGADeviceOnTheSameSegment (PciIoDevice);
+  Temp = LocateVgaDeviceOnHostBridge (PciIoDevice->PciRootBridgeIo->ParentHandle);
 
   if (Temp == NULL) {
     //
@@ -1670,7 +1670,7 @@ PciIoAttributes (
         //
         // Check if there have been an active VGA device on the same segment
         //
-        Temp = ActiveVGADeviceOnTheSameSegment (PciIoDevice);
+        Temp = LocateVgaDeviceOnHostBridge (PciIoDevice->PciRootBridgeIo->ParentHandle);
         if (Temp != NULL && Temp != PciIoDevice) {
           //
           // An active VGA has been detected, so can not enable another
-- 
2.16.1.windows.1