[reactos] 18/18: [WIN32SS] Enable multidisplay driver when required

[Hervé Poussineau]

https://git.reactos.org/?p=reactos.git;a=commitdiff;h=9400063aae0bd68858f700...

commit 9400063aae0bd68858f7002385fe68238ba8a37e
Author:     Hervé Poussineau [e-mail]
AuthorDate: Sun Mar 20 18:12:11 2022 +0100
Commit:     hpoussin [e-mail]
CommitDate: Fri Apr 15 23:09:16 2022 +0200

[WIN32SS] Enable multidisplay driver when required

For now, it is only a stub which returns an error.
---
 win32ss/CMakeLists.txt      |  1 +
 win32ss/gdi/eng/multidisp.c | 24 ++++++++++++++++++++++++
 win32ss/gdi/eng/pdevobj.c   | 24 +++++++++++++++++++-----
 3 files changed, 44 insertions(+), 5 deletions(-)

diff --git a/win32ss/CMakeLists.txt b/win32ss/CMakeLists.txt
index a786921291c..a5efa7f9f16 100644
--- a/win32ss/CMakeLists.txt
+++ b/win32ss/CMakeLists.txt
@@ -77,6 +77,7 @@ list(APPEND SOURCE
     gdi/eng/mem.c
     gdi/eng/engmisc.c
     gdi/eng/mouse.c
+    gdi/eng/multidisp.c
     gdi/eng/paint.c
     gdi/eng/pathobj.c
     gdi/eng/pdevobj.c
diff --git a/win32ss/gdi/eng/multidisp.c b/win32ss/gdi/eng/multidisp.c
new file mode 100644
index 00000000000..e815e19939d
--- /dev/null
+++ b/win32ss/gdi/eng/multidisp.c
@@ -0,0 +1,24 @@
+/*
+* PROJECT:     ReactOS Win32k subsystem
+* LICENSE:     GPL-2.0-or-later (https://spdx.org/licenses/GPL-2.0-or-later)
+* FILE:        win32ss/gdi/eng/multidisp.c
+* PURPOSE:     Multi-Display driver
+* PROGRAMMERS:
+*/
+
+/* INCLUDES *******************************************************************/
+
+#include <win32k.h>
+#define NDEBUG
+#include <debug.h>
+
+BOOL
+APIENTRY
+MultiEnableDriver(
+    _In_ ULONG iEngineVersion,
+    _In_ ULONG cj,
+    _Inout_bytecount_(cj) PDRVENABLEDATA pded)
+{
+    UNIMPLEMENTED;
+    return FALSE;
+}
diff --git a/win32ss/gdi/eng/pdevobj.c b/win32ss/gdi/eng/pdevobj.c
index f39afd18530..41c5045ef2c 100644
--- a/win32ss/gdi/eng/pdevobj.c
+++ b/win32ss/gdi/eng/pdevobj.c
@@ -14,6 +14,13 @@ DBG_DEFAULT_CHANNEL(EngPDev);
 static PPDEVOBJ gppdevList = NULL;
 static HSEMAPHORE ghsemPDEV;

+BOOL
+APIENTRY
+MultiEnableDriver(
+    _In_ ULONG iEngineVersion,
+    _In_ ULONG cj,
+    _Inout_bytecount_(cj) PDRVENABLEDATA pded);
+
 CODE_SEG("INIT")
 NTSTATUS
 NTAPI
@@ -456,7 +463,10 @@ PDEVOBJ_Create(
     }

/* Try to get a display driver */
-    pldev = LDEVOBJ_pLoadDriver(pdm->dmDeviceName, ldevtype);
+    if (ldevtype == LDEV_DEVICE_META)
+        pldev = LDEVOBJ_pLoadInternal(MultiEnableDriver, ldevtype);
+    else
+        pldev = LDEVOBJ_pLoadDriver(pdm->dmDeviceName, ldevtype);
     if (!pldev)
     {
         ERR("Could not load display driver '%S'\n",
@@ -877,10 +887,14 @@ PDEVOBJ_lChangeDisplaySettings(
         }
         else
         {
-            /* FIXME: currently, only use the first display */
-            UNIMPLEMENTED;
-            PDEVOBJ_vReference(pmdev->dev[0].ppdev);
-            pmdev->ppdevGlobal = pmdev->dev[0].ppdev;
+            /* Enable MultiDriver */
+            pmdev->ppdevGlobal = PDEVOBJ_Create(NULL, (PDEVMODEW)pmdev, 0, LDEV_DEVICE_META);
+            if (!pmdev->ppdevGlobal)
+            {
+                WARN("Failed to create meta-device. Using only first display\n");
+                PDEVOBJ_vReference(pmdev->dev[0].ppdev);
+                pmdev->ppdevGlobal = pmdev->dev[0].ppdev;
+            }
         }

if (pmdevOld)