From e5b4190710ca7dafe040c4259edad2cd7519d5f3 Mon Sep 17 00:00:00 2001
From: Filip Navara <filip.navara@gmail.com>
Date: Mon, 26 May 2008 18:32:40 +0000
Subject: [PATCH] Fix incorrect logic in IntVideoPortSetupInterrupt and add
 comment.

svn path=/trunk/; revision=33717
---
 reactos/drivers/video/videoprt/interrupt.c | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/reactos/drivers/video/videoprt/interrupt.c b/reactos/drivers/video/videoprt/interrupt.c
index 06407aa1eda..6dd8e0f1fae 100644
--- a/reactos/drivers/video/videoprt/interrupt.c
+++ b/reactos/drivers/video/videoprt/interrupt.c
@@ -48,13 +48,17 @@ IntVideoPortSetupInterrupt(
 
    DeviceExtension = (PVIDEO_PORT_DEVICE_EXTENSION)DeviceObject->DeviceExtension;
 
-   if (ConfigInfo->BusInterruptVector == 0)
-      ConfigInfo->BusInterruptVector = DeviceExtension->InterruptVector;
+   /*
+    * MSDN documentation for VIDEO_PORT_CONFIG_INFO states: "If a miniport driver's
+    * HwVidFindAdapter function finds that the video adapter does not generate
+    * interrupts or that it cannot determine a valid interrupt vector/level for
+    * the adapter, HwVidFindAdapter should set both BusInterruptVector and
+    * BusInterruptLevel to zero.
+    */
 
-   if (ConfigInfo->BusInterruptLevel == 0)
-      ConfigInfo->BusInterruptLevel = DeviceExtension->InterruptLevel;
-
-   if (DriverExtension->InitializationData.HwInterrupt != NULL)
+   if (DriverExtension->InitializationData.HwInterrupt != NULL &&
+       ConfigInfo->BusInterruptLevel != 0 &&
+       ConfigInfo->BusInterruptVector != 0)
    {
       ULONG InterruptVector;
       KIRQL Irql;