[PATCH v3 3/9] win32u: Keep the source depth separately from the current mode.

[Rémi Bernon]

From: Rémi Bernon

The host may not actually have support for the selected depth, when
emulating 8 or 16bpp display modes, and we'll get display device updates
with the default display depth instead.

We still want to report the desired display depth to the applications,
so keep it with the sources.
---
 dlls/win32u/sysparams.c | 49 ++++++++++++++++++-----------------------
 1 file changed, 21 insertions(+), 28 deletions(-)

diff --git a/dlls/win32u/sysparams.c b/dlls/win32u/sysparams.c
index a995432d01c..86c3a9de025 100644
--- a/dlls/win32u/sysparams.c
+++ b/dlls/win32u/sysparams.c
@@ -71,6 +71,7 @@ static const WCHAR noW[] = {'N','o',0};
 static const WCHAR modesW[] = {'M','o','d','e','s',0};
 static const WCHAR mode_countW[] = {'M','o','d','e','C','o','u','n','t',0};
 static const WCHAR dpiW[] = {'D','p','i',0};
+static const WCHAR depthW[] = {'D','e','p','t','h',0};

static const char  guid_devclass_displayA[] = "{4D36E968-E325-11CE-BFC1-08002BE10318}";
 static const WCHAR guid_devclass_displayW[] =
@@ -108,6 +109,7 @@ struct source
     unsigned int id;
     struct gpu *gpu;
     UINT dpi;
+    UINT depth; /* emulated depth */
     UINT state_flags;
     UINT monitor_count;
     UINT mode_count;
@@ -509,20 +511,20 @@ static BOOL source_get_current_settings( const struct source *source, DEVMODEW *
     if (is_virtual_desktop()) ret = FALSE;
     else ret = user_driver->pGetCurrentDisplaySettings( device_nameW, is_primary, mode );

-    if (ret) return TRUE;
-
-    /* default implementation: read current display settings from the registry. */
-
-    mutex = get_display_device_init_mutex();
-
-    if (!(hkey = reg_open_ascii_key( config_key, source->path ))) ret = FALSE;
-    else
+    if (!ret)
     {
-        ret = read_source_mode( hkey, ENUM_CURRENT_SETTINGS, mode );
-        NtClose( hkey );
+        /* default implementation: read current display settings from the registry. */
+        mutex = get_display_device_init_mutex();
+        if (!(hkey = reg_open_ascii_key( config_key, source->path ))) ret = FALSE;
+        else
+        {
+            ret = read_source_mode( hkey, ENUM_CURRENT_SETTINGS, mode );
+            NtClose( hkey );
+        }
+        release_display_device_init_mutex( mutex );
     }

-    release_display_device_init_mutex( mutex );
+    if (ret && source->depth) mode->dmBitsPerPel = source->depth;
     return ret;
 }

@@ -538,6 +540,7 @@ static BOOL source_set_current_settings( const struct source *source, const DEVM
     else
     {
         ret = write_source_mode( hkey, ENUM_CURRENT_SETTINGS, mode );
+        if (ret) set_reg_value( hkey, depthW, REG_DWORD, &mode->dmBitsPerPel, sizeof(mode->dmBitsPerPel) );
         NtClose( hkey );
     }

@@ -649,6 +652,10 @@ static BOOL read_source_from_registry( unsigned int index, struct source *source
     if (query_reg_ascii_value( hkey, "Dpi", value, sizeof(buffer) ) && value->Type == REG_DWORD)
         source->dpi = *(DWORD *)value->Data;

+    /* Depth */
+    if (query_reg_ascii_value( hkey, "Depth", value, sizeof(buffer) ) && value->Type == REG_DWORD)
+        source->depth = *(const DWORD *)value->Data;
+
     /* ModeCount */
     if (query_reg_ascii_value( hkey, "ModeCount", value, sizeof(buffer) ) && value->Type == REG_DWORD)
         source->mode_count = *(const DWORD *)value->Data;
@@ -3641,10 +3648,8 @@ static unsigned int active_unique_monitor_count(void)

INT get_display_depth( UNICODE_STRING *name )
 {
-    WCHAR device_nameW[CCHDEVICENAME];
-    char device_name[CCHDEVICENAME];
+    DEVMODEW current_mode = {.dmSize = sizeof(DEVMODEW)};
     struct source *source;
-    BOOL is_primary;
     INT depth;

if (!lock_display_devices())
@@ -3659,20 +3664,8 @@ INT get_display_depth( UNICODE_STRING *name )
         return 32;
     }

-    is_primary = !!(source->state_flags & DISPLAY_DEVICE_PRIMARY_DEVICE);
-    snprintf( device_name, sizeof(device_name), "\\.\DISPLAY%d", source->id + 1 );
-    asciiz_to_unicode( device_nameW, device_name );
-
-    /* use the default implementation in virtual desktop mode */
-    if (is_virtual_desktop()) depth = -1;
-    else depth = user_driver->pGetDisplayDepth( device_nameW, is_primary );
-
-    if (depth < 0)
-    {
-        DEVMODEW current_mode = {.dmSize = sizeof(DEVMODEW)};
-        if (!source_get_current_settings( source, &current_mode )) depth = 32;
-        else depth = current_mode.dmBitsPerPel;
-    }
+    if (!source_get_current_settings( source, &current_mode )) depth = 32;
+    else depth = current_mode.dmBitsPerPel;

unlock_display_devices();
     return depth;