From ae157bec34a132d34ed04005f02f9fdf4845af97 Mon Sep 17 00:00:00 2001
From: Zhiyi Zhang <zzhang@codeweavers.com>
Date: Tue, 11 Feb 2020 16:08:59 +0800
Subject: [PATCH] user32: Handle NULL device and not NULL mode parameters in
 ChangeDisplaySettingsExW().

This makes sure that user graphics drivers has a valid device name when a
DEVMODE is specified.

Signed-off-by: Zhiyi Zhang <zzhang@codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>
---
 dlls/user32/sysparams.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/dlls/user32/sysparams.c b/dlls/user32/sysparams.c
index e3919ad1b10..c5c98a7ea1c 100644
--- a/dlls/user32/sysparams.c
+++ b/dlls/user32/sysparams.c
@@ -3293,12 +3293,21 @@ static void trace_devmode(const DEVMODEW *devmode)
 LONG WINAPI ChangeDisplaySettingsExW( LPCWSTR devname, LPDEVMODEW devmode, HWND hwnd,
                                       DWORD flags, LPVOID lparam )
 {
+    WCHAR primary_adapter[CCHDEVICENAME];
     BOOL def_mode = TRUE;
     DEVMODEW dm;
 
     TRACE("%s %p %p %#x %p\n", debugstr_w(devname), devmode, hwnd, flags, lparam);
     TRACE("flags=%s\n", _CDS_flags(flags));
 
+    if (!devname && devmode)
+    {
+        if (!get_primary_adapter(primary_adapter))
+            return DISP_CHANGE_FAILED;
+
+        devname = primary_adapter;
+    }
+
     if (devmode)
     {
         trace_devmode(devmode);