[PATCH 4/5] win32u: Introduce a new registry setting to emulate modesetting.

[Rémi Bernon]

From: Rémi Bernon

---
 dlls/win32u/sysparams.c | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/dlls/win32u/sysparams.c b/dlls/win32u/sysparams.c
index fefd836d4f5..cc27f3dc7f2 100644
--- a/dlls/win32u/sysparams.c
+++ b/dlls/win32u/sysparams.c
@@ -158,6 +158,7 @@ static struct list monitors = LIST_INIT(monitors);
 static INT64 last_query_display_time;
 static pthread_mutex_t display_lock = PTHREAD_MUTEX_INITIALIZER;

+static BOOL emulate_modeset;
 BOOL decorated_mode = TRUE;
 UINT64 thunk_lock_callback = 0;

@@ -1655,8 +1656,7 @@ static DEVMODEW *get_virtual_modes( const DEVMODEW *current, const DEVMODEW *ini
 static void add_modes( const DEVMODEW *current, UINT modes_count, const DEVMODEW *modes, void *param )
 {
     struct device_manager_ctx *ctx = param;
-    DEVMODEW dummy, detached = *current, virtual, *virtual_modes = NULL;
-    const DEVMODEW physical = modes_count == 1 ? *modes : *current;
+    DEVMODEW dummy, physical, detached = *current, virtual, *virtual_modes = NULL;
     struct source *source;
     UINT virtual_count;

@@ -1665,6 +1665,13 @@ static void add_modes( const DEVMODEW *current, UINT modes_count, const DEVMODEW
     assert( !list_empty( &sources ) );
     source = LIST_ENTRY( list_tail( &sources ), struct source, entry );

+    if (emulate_modeset)
+    {
+        modes = current;
+        modes_count = 1;
+    }
+
+    physical = modes_count == 1 ? *modes : *current;
     if (ctx->is_primary) ctx->primary = *current;

detached.dmPelsWidth = 0;
@@ -3851,7 +3858,7 @@ static LONG apply_display_settings( struct source *target, const DEVMODEW *devmo
     place_all_displays( displays, primary_name );

/* use the default implementation in virtual desktop mode */
-    if (is_virtual_desktop()) ret = DISP_CHANGE_SUCCESSFUL;
+    if (is_virtual_desktop() || emulate_modeset) ret = DISP_CHANGE_SUCCESSFUL;
     else ret = user_driver->pChangeDisplaySettings( displays, primary_name, hwnd, flags, lparam );

if (ret == DISP_CHANGE_SUCCESSFUL)
@@ -5423,6 +5430,8 @@ void sysparams_init(void)
         grab_fullscreen = IS_OPTION_TRUE( buffer[0] );
     if (!get_config_key( hkey, appkey, "Decorated", buffer, sizeof(buffer) ))
         decorated_mode = IS_OPTION_TRUE( buffer[0] );
+    if (!get_config_key( hkey, appkey, "EmulateModeset", buffer, sizeof(buffer) ))
+        emulate_modeset = IS_OPTION_TRUE( buffer[0] );

#undef IS_OPTION_TRUE