[PATCH v2 0/2] MR8718: win32u: Create Vulkan swapchains with VkSwapchainPresentScalingCreateInfoEXT when the surface will be scaled.

[Brendan Shanks (＠bshanks)]

If the swapchain image size is not equal to the presentation size (e.g. because of DPI virtualization or display mode change emulation), MoltenVK's `vkQueuePresentKHR` returns `VK_SUBOPTIMAL_KHR` (see [`MVKSwapchain::hasOptimalSurface()`](https://github.com/KhronosGroup/MoltenVK/blob/a046e779df332f5c23a03df1cb6de4...). I can see this with a vkcube hacked to run in fullscreen, and it's especially problematic with wined3d which recreates the swapchain on `VK_SUBOPTIMAL_KHR` (every frame).

Create the swapchain with `VkSwapchainPresentScalingCreateInfoEXT` when the window is being scaled to avoid this. I'm not sure if it's proper to be enabling the extension in winevulkan and then using it in win32u, but I don't see an obvious way to hook `vkCreateDevice` in win32u.

--
  v2: win32u: Create Vulkan swapchains with VkSwapchainPresentScalingCreateInfoEXT when the surface will be scaled.
      winevulkan: Enable VK_EXT_swapchain_maintenance1 when available.

https://gitlab.winehq.org/wine/wine/-/merge_requests/8718

[PATCH v2 1/2] winevulkan: Enable VK_EXT_swapchain_maintenance1 when available.

[Brendan Shanks]

From: Brendan Shanks

---
 dlls/winevulkan/vulkan.c     | 11 ++++++++++-
 include/wine/vulkan_driver.h |  2 ++
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/dlls/winevulkan/vulkan.c b/dlls/winevulkan/vulkan.c
index 61b3a42d63f..ac93931092b 100644
--- a/dlls/winevulkan/vulkan.c
+++ b/dlls/winevulkan/vulkan.c
@@ -384,6 +384,8 @@ static VkResult wine_vk_physical_device_init(struct wine_phys_dev *object, VkPhy
             have_external_memory_host = TRUE;
         else if (!strcmp(host_properties[i].extensionName, "VK_EXT_map_memory_placed"))
             have_memory_placed = TRUE;
+        else if (!strcmp(host_properties[i].extensionName, "VK_EXT_swapchain_maintenance1"))
+            object->obj.has_swapchain_maintenance1 = true;
         else if (!strcmp(host_properties[i].extensionName, "VK_KHR_map_memory2"))
             have_map_memory2 = TRUE;
     }
@@ -545,7 +547,7 @@ static VkResult wine_vk_device_convert_create_info(VkPhysicalDevice client_physi
         struct conversion_context *ctx, const VkDeviceCreateInfo *src, VkDeviceCreateInfo *dst)
 {
     struct wine_phys_dev *phys_dev = wine_phys_dev_from_handle(client_physical_device);
-    const char *extra_extensions[2], * const*extensions = src->ppEnabledExtensionNames;
+    const char *extra_extensions[3], * const*extensions = src->ppEnabledExtensionNames;
     unsigned int i, extra_count = 0, extensions_count = src->enabledExtensionCount;

*dst = *src;
@@ -590,6 +592,13 @@ static VkResult wine_vk_device_convert_create_info(VkPhysicalDevice client_physi
             extra_extensions[extra_count++] = "VK_EXT_external_memory_host";
     }

+    /* win32u uses VkSwapchainPresentScalingCreateInfoEXT if available. */
+    if (phys_dev->obj.has_swapchain_maintenance1)
+    {
+        if (!find_extension(extensions, extensions_count, "VK_EXT_swapchain_maintenance1"))
+            extra_extensions[extra_count++] = "VK_EXT_swapchain_maintenance1";
+    }
+
     if (extra_count)
     {
         const char **new_extensions;
diff --git a/include/wine/vulkan_driver.h b/include/wine/vulkan_driver.h
index 55613f3211f..0579ea7773f 100644
--- a/include/wine/vulkan_driver.h
+++ b/include/wine/vulkan_driver.h
@@ -21,6 +21,7 @@
 #define __WINE_VULKAN_DRIVER_H

#include <stdarg.h>
+#include <stdbool.h>
 #include <stddef.h>

#include <windef.h>
@@ -90,6 +91,7 @@ struct vulkan_physical_device
 {
     VULKAN_OBJECT_HEADER( VkPhysicalDevice, physical_device );
     struct vulkan_instance *instance;
+    bool has_swapchain_maintenance1;
 };

static inline struct vulkan_physical_device *vulkan_physical_device_from_handle( VkPhysicalDevice handle )

[PATCH v2 2/2] win32u: Create Vulkan swapchains with VkSwapchainPresentScalingCreateInfoEXT when the surface will be scaled.

[Brendan Shanks]

From: Brendan Shanks

---
 dlls/win32u/vulkan.c | 24 +++++++++++++++++++-----
 1 file changed, 19 insertions(+), 5 deletions(-)

diff --git a/dlls/win32u/vulkan.c b/dlls/win32u/vulkan.c
index 2e0c4627d71..722bdd845cf 100644
--- a/dlls/win32u/vulkan.c
+++ b/dlls/win32u/vulkan.c
@@ -269,9 +269,15 @@ static VkBool32 win32u_vkGetPhysicalDeviceWin32PresentationSupportKHR( VkPhysica
     return driver_funcs->p_vkGetPhysicalDeviceWin32PresentationSupportKHR( physical_device->host.physical_device, queue );
 }

+static BOOL extents_equals( const VkExtent2D *extents, const RECT *rect )
+{
+    return extents->width == rect->right - rect->left && extents->height == rect->bottom - rect->top;
+}
+
 static VkResult win32u_vkCreateSwapchainKHR( VkDevice client_device, const VkSwapchainCreateInfoKHR *create_info,
                                              const VkAllocationCallbacks *allocator, VkSwapchainKHR *ret )
 {
+    VkSwapchainPresentScalingCreateInfoEXT scaling = {.sType = VK_STRUCTURE_TYPE_SWAPCHAIN_PRESENT_SCALING_CREATE_INFO_EXT};
     struct swapchain *swapchain, *old_swapchain = swapchain_from_handle( create_info->oldSwapchain );
     struct surface *surface = surface_from_handle( create_info->surface );
     struct vulkan_device *device = vulkan_device_from_handle( client_device );
@@ -280,6 +286,7 @@ static VkResult win32u_vkCreateSwapchainKHR( VkDevice client_device, const VkSwa
     VkSwapchainCreateInfoKHR create_info_host = *create_info;
     VkSurfaceCapabilitiesKHR capabilities;
     VkSwapchainKHR host_swapchain;
+    RECT client_rect;
     VkResult res;

if (!NtUserIsWindow( surface->hwnd ))
@@ -298,6 +305,18 @@ static VkResult win32u_vkCreateSwapchainKHR( VkDevice client_device, const VkSwa
     create_info_host.imageExtent.width = max( create_info_host.imageExtent.width, capabilities.minImageExtent.width );
     create_info_host.imageExtent.height = max( create_info_host.imageExtent.height, capabilities.minImageExtent.height );

+    /* If the swapchain image size is not equal to the presentation size (e.g. because of DPI virtualization or
+     * display mode change emulation), MoltenVK's vkQueuePresentKHR returns VK_SUBOPTIMAL_KHR.
+     * Create the swapchain with VkSwapchainPresentScalingCreateInfoEXT to avoid this.
+     */
+    if (NtUserGetClientRect( surface->hwnd, &client_rect, NtUserGetWinMonitorDpi( surface->hwnd, MDT_RAW_DPI ) ) &&
+        !extents_equals( &create_info_host.imageExtent, &client_rect ) &&
+        physical_device->has_swapchain_maintenance1)
+    {
+        scaling.scalingBehavior = VK_PRESENT_SCALING_STRETCH_BIT_EXT;
+        create_info_host.pNext = &scaling;
+    }
+
     if (!(swapchain = calloc( 1, sizeof(*swapchain) ))) return VK_ERROR_OUT_OF_HOST_MEMORY;

if ((res = device->p_vkCreateSwapchainKHR( device->host.device, &create_info_host, NULL, &host_swapchain )))
@@ -331,11 +350,6 @@ void win32u_vkDestroySwapchainKHR( VkDevice client_device, VkSwapchainKHR client
     free( swapchain );
 }

-static BOOL extents_equals( const VkExtent2D *extents, const RECT *rect )
-{
-    return extents->width == rect->right - rect->left && extents->height == rect->bottom - rect->top;
-}
-
 static VkResult win32u_vkAcquireNextImage2KHR( VkDevice client_device, const VkAcquireNextImageInfoKHR *acquire_info,
                                                uint32_t *image_index )
 {

[Brendan Shanks (＠bshanks)]

On Thu Aug  7 22:58:30 2025 +0000, Brendan Shanks wrote:
> changed this line in [version 2 of the diff](/wine/wine/-/merge_requests/8718/diffs?diff_id=199320&start_sha=c6c8d93418864258118170130c9d9add6951767b#05000c6e183209e030beb05f7baba884c43ccc3e_83_83)

Yes that simplifies things, thanks!

[PATCH v2 0/2] MR8718: win32u: Create Vulkan swapchains with VkSwapchainPresentScalingCreateInfoEXT when the surface will be scaled. - approved

[Rémi Bernon (＠rbernon)]

This merge request was approved by Rémi Bernon.