OvmfPkg: QemuVideoDxe: disentangle UEFI driver model use in Stop()

A bus driver needs to pay attention whether its Stop() function is being
called on the "main" controller handle (NumberOfChildren == 0) or on the
child handles (NumberOfChildren > 0).

In QemuVideoDxe, all our resources are associated with the one child
handle (and the Private data structure) *except* the top-level PciIo
protocol reference. Be conscious of which mode Stop() is being called for.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@15284 6f19259b-4bc3-4df7-8a09-765794883524

1 files changed, 20 insertions, 11 deletions

diff --git a/OvmfPkg/QemuVideoDxe/Driver.c b/OvmfPkg/QemuVideoDxe/Driver.c
index 508e1acb10..48a788f6f8 100644
--- a/OvmfPkg/QemuVideoDxe/Driver.c
+++ b/OvmfPkg/QemuVideoDxe/Driver.c
@@ -454,8 +454,26 @@ QemuVideoControllerDriverStop (
   EFI_STATUS                      Status;

   QEMU_VIDEO_PRIVATE_DATA  *Private;

 

+  if (NumberOfChildren == 0) {

+    //

+    // Close the PCI I/O Protocol

+    //

+    gBS->CloseProtocol (

+          Controller,

+          &gEfiPciIoProtocolGuid,

+          This->DriverBindingHandle,

+          Controller

+          );

+    return EFI_SUCCESS;

+  }

+

+  //

+  // free all resources for whose access we need the child handle, because the

+  // child handle is going away

+  //

+  ASSERT (NumberOfChildren == 1);

   Status = gBS->OpenProtocol (

-                  Controller,

+                  ChildHandleBuffer[0],

                   &gEfiGraphicsOutputProtocolGuid,

                   (VOID **) &GraphicsOutput,

                   This->DriverBindingHandle,

@@ -470,6 +488,7 @@ QemuVideoControllerDriverStop (
   // Get our private context information

   //

   Private = QEMU_VIDEO_PRIVATE_DATA_FROM_GRAPHICS_OUTPUT_THIS (GraphicsOutput);

+  ASSERT (Private->Handle == ChildHandleBuffer[0]);

 

   QemuVideoGraphicsOutputDestructor (Private);

   //

@@ -496,16 +515,6 @@ QemuVideoControllerDriverStop (
                   NULL

                   );

 

-  //

-  // Close the PCI I/O Protocol

-  //

-  gBS->CloseProtocol (

-        Controller,

-        &gEfiPciIoProtocolGuid,

-        This->DriverBindingHandle,

-        Controller

-        );

-

   gBS->CloseProtocol (

         Controller,

         &gEfiPciIoProtocolGuid,