wsi: allow to override the present mode with MESA_VK_WSI_PRESENT_MODE

This is common to all Vulkan drivers and all WSI.

Signed-off-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>

src/vulkan/wsi/wsi_common.c

@@ -29,6 +29,8 @@
 #include <time.h>
 #include <unistd.h>
 #include <xf86drm.h>
+#include <stdlib.h>
+#include <stdio.h>
 
 VkResult
 wsi_device_init(struct wsi_device *wsi,
@@ -37,6 +39,7 @@ wsi_device_init(struct wsi_device *wsi,
                 const VkAllocationCallbacks *alloc,
                 int display_fd)
 {
+   const char *present_mode;
    VkResult result;
 
    memset(wsi, 0, sizeof(*wsi));
@@ -60,6 +63,7 @@ wsi_device_init(struct wsi_device *wsi,
    GetPhysicalDeviceProperties2(pdevice, &pdp2);
 
    wsi->maxImageDimension2D = pdp2.properties.limits.maxImageDimension2D;
+   wsi->override_present_mode = VK_PRESENT_MODE_MAX_ENUM_KHR;
 
    GetPhysicalDeviceMemoryProperties(pdevice, &wsi->memory_props);
    GetPhysicalDeviceQueueFamilyProperties(pdevice, &wsi->queue_family_count, NULL);
@@ -112,6 +116,19 @@ wsi_device_init(struct wsi_device *wsi,
       goto fail;
 #endif
 
+   present_mode = getenv("MESA_VK_WSI_PRESENT_MODE");
+   if (present_mode) {
+      if (!strcmp(present_mode, "fifo")) {
+         wsi->override_present_mode = VK_PRESENT_MODE_FIFO_KHR;
+      } else if (!strcmp(present_mode, "mailbox")) {
+         wsi->override_present_mode = VK_PRESENT_MODE_MAILBOX_KHR;
+      } else if (!strcmp(present_mode, "immediate")) {
+         wsi->override_present_mode = VK_PRESENT_MODE_IMMEDIATE_KHR;
+      } else {
+         fprintf(stderr, "Invalid MESA_VK_WSI_PRESENT_MODE value!\n");
+      }
+   }
+
    return VK_SUCCESS;
 
 fail:
@@ -202,6 +219,59 @@ fail:
    return result;
 }
 
+static bool
+wsi_swapchain_is_present_mode_supported(struct wsi_device *wsi,
+                                        const VkSwapchainCreateInfoKHR *pCreateInfo,
+                                        VkPresentModeKHR mode)
+{
+      ICD_FROM_HANDLE(VkIcdSurfaceBase, surface, pCreateInfo->surface);
+      struct wsi_interface *iface = wsi->wsi[surface->platform];
+      VkPresentModeKHR *present_modes;
+      uint32_t present_mode_count;
+      bool supported = false;
+      VkResult result;
+
+      result = iface->get_present_modes(surface, &present_mode_count, NULL);
+      if (result != VK_SUCCESS)
+         return supported;
+
+      present_modes = malloc(present_mode_count * sizeof(*present_modes));
+      if (!present_modes)
+         return supported;
+
+      result = iface->get_present_modes(surface, &present_mode_count,
+                                        present_modes);
+      if (result != VK_SUCCESS)
+         goto fail;
+
+      for (uint32_t i = 0; i < present_mode_count; i++) {
+         if (present_modes[i] == mode) {
+            supported = true;
+            break;
+         }
+      }
+
+fail:
+      free(present_modes);
+      return supported;
+}
+
+enum VkPresentModeKHR
+wsi_swapchain_get_present_mode(struct wsi_device *wsi,
+                               const VkSwapchainCreateInfoKHR *pCreateInfo)
+{
+   if (wsi->override_present_mode == VK_PRESENT_MODE_MAX_ENUM_KHR)
+      return pCreateInfo->presentMode;
+
+   if (!wsi_swapchain_is_present_mode_supported(wsi, pCreateInfo,
+                                                wsi->override_present_mode)) {
+      fprintf(stderr, "Unsupported MESA_VK_WSI_PRESENT_MODE value!\n");
+      return pCreateInfo->presentMode;
+   }
+
+   return wsi->override_present_mode;
+}
+
 void
 wsi_swapchain_finish(struct wsi_swapchain *chain)
 {

src/vulkan/wsi/wsi_common.h

@@ -101,6 +101,7 @@ struct wsi_device {
 
    bool supports_modifiers;
    uint32_t maxImageDimension2D;
+   VkPresentModeKHR override_present_mode;
 
    uint64_t (*image_get_modifier)(VkImage image);
 

src/vulkan/wsi/wsi_common_display.c

@@ -1757,7 +1757,7 @@ wsi_display_surface_create_swapchain(
    chain->base.get_wsi_image = wsi_display_get_wsi_image;
    chain->base.acquire_next_image = wsi_display_acquire_next_image;
    chain->base.queue_present = wsi_display_queue_present;
-   chain->base.present_mode = create_info->presentMode;
+   chain->base.present_mode = wsi_swapchain_get_present_mode(wsi_device, create_info);
    chain->base.image_count = num_images;
 
    chain->wsi = wsi;

src/vulkan/wsi/wsi_common_private.h

@@ -79,6 +79,10 @@ wsi_swapchain_init(const struct wsi_device *wsi,
                    const VkSwapchainCreateInfoKHR *pCreateInfo,
                    const VkAllocationCallbacks *pAllocator);
 
+enum VkPresentModeKHR
+wsi_swapchain_get_present_mode(struct wsi_device *wsi,
+                               const VkSwapchainCreateInfoKHR *pCreateInfo);
+
 void wsi_swapchain_finish(struct wsi_swapchain *chain);
 
 VkResult

src/vulkan/wsi/wsi_common_wayland.c

@@ -1009,7 +1009,7 @@ wsi_wl_surface_create_swapchain(VkIcdSurfaceBase *icd_surface,
    chain->base.get_wsi_image = wsi_wl_swapchain_get_wsi_image;
    chain->base.acquire_next_image = wsi_wl_swapchain_acquire_next_image;
    chain->base.queue_present = wsi_wl_swapchain_queue_present;
-   chain->base.present_mode = pCreateInfo->presentMode;
+   chain->base.present_mode = wsi_swapchain_get_present_mode(wsi_device, pCreateInfo);
    chain->base.image_count = num_images;
    chain->extent = pCreateInfo->imageExtent;
    chain->vk_format = pCreateInfo->imageFormat;

src/vulkan/wsi/wsi_common_x11.c

@@ -1361,7 +1361,7 @@ x11_surface_create_swapchain(VkIcdSurfaceBase *icd_surface,
    chain->base.get_wsi_image = x11_get_wsi_image;
    chain->base.acquire_next_image = x11_acquire_next_image;
    chain->base.queue_present = x11_queue_present;
-   chain->base.present_mode = pCreateInfo->presentMode;
+   chain->base.present_mode = wsi_swapchain_get_present_mode(wsi_device, pCreateInfo);
    chain->base.image_count = num_images;
    chain->conn = conn;
    chain->window = window;