vulkan/wsi/wl: correctly find whether the compositor uses the same GPU

Using the wl_drm protocol we can check whether the compositor uses the
same GPU as the application.

This allows to run vulkan applications using a DG2 GPU with the
compositor using another card.

Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Cc: mesa-stable
Reviewed-by: Simon Ser <contact@emersion.fr>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/19224>

src/vulkan/wsi/wsi_common.c

@@ -87,8 +87,11 @@ wsi_device_init(struct wsi_device *wsi,
    WSI_GET_CB(GetPhysicalDeviceQueueFamilyProperties);
 #undef WSI_GET_CB
 
+   wsi->drm_info.sType =
+      VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_DRM_PROPERTIES_EXT;
    wsi->pci_bus_info.sType =
       VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_PCI_BUS_INFO_PROPERTIES_EXT;
+   wsi->pci_bus_info.pNext = &wsi->drm_info;
    VkPhysicalDeviceProperties2 pdp2 = {
       .sType = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_PROPERTIES_2,
       .pNext = &wsi->pci_bus_info,

src/vulkan/wsi/wsi_common.h

@@ -100,6 +100,7 @@ struct wsi_device {
    VkPhysicalDeviceMemoryProperties memory_props;
    uint32_t queue_family_count;
 
+   VkPhysicalDeviceDrmPropertiesEXT drm_info;
    VkPhysicalDevicePCIBusInfoPropertiesEXT pci_bus_info;
 
    VkExternalSemaphoreHandleTypeFlags semaphore_export_handle_types;

src/vulkan/wsi/wsi_common_wayland.c

@@ -50,6 +50,13 @@
 #include <util/u_dynarray.h>
 #include <util/anon_file.h>
 
+#ifdef MAJOR_IN_MKDEV
+#include <sys/mkdev.h>
+#endif
+#ifdef MAJOR_IN_SYSMACROS
+#include <sys/sysmacros.h>
+#endif
+
 struct wsi_wayland;
 
 struct wsi_wl_format {
@@ -99,6 +106,9 @@ struct wsi_wl_display {
    struct u_vector formats;
 
    bool sw;
+
+   dev_t main_device;
+   bool same_gpu;
 };
 
 struct wsi_wayland {
@@ -633,7 +643,11 @@ default_dmabuf_feedback_main_device(void *data,
                                     struct zwp_linux_dmabuf_feedback_v1 *dmabuf_feedback,
                                     struct wl_array *device)
 {
-   /* ignore this event */
+   struct wsi_wl_display *display = data;
+
+   assert(device->size == sizeof(dev_t));
+   dev_t *dev = device->data;
+   display->main_device = *dev;
 }
 
 static void
@@ -814,6 +828,9 @@ wsi_wl_display_init(struct wsi_wayland *wsi_wl,
    if (!get_format_list)
       goto out;
 
+   /* Default assumption */
+   display->same_gpu = true;
+
    /* Get the default dma-buf feedback */
    if (display->wl_dmabuf && zwp_linux_dmabuf_v1_get_version(display->wl_dmabuf) >=
                              ZWP_LINUX_DMABUF_V1_GET_DEFAULT_FEEDBACK_SINCE_VERSION) {
@@ -822,6 +839,15 @@ wsi_wl_display_init(struct wsi_wayland *wsi_wl,
             zwp_linux_dmabuf_v1_get_default_feedback(display->wl_dmabuf);
          zwp_linux_dmabuf_feedback_v1_add_listener(display->wl_dmabuf_feedback,
                                                    &dmabuf_feedback_listener, display);
+
+         /* Round-trip again to fetch dma-buf feedback */
+         wl_display_roundtrip_queue(display->wl_display, display->queue);
+
+         if (wsi_wl->wsi->drm_info.hasRender) {
+            display->same_gpu =
+               major(display->main_device) == wsi_wl->wsi->drm_info.renderMajor &&
+               minor(display->main_device) == wsi_wl->wsi->drm_info.renderMinor;
+         }
    }
 
    /* Round-trip again to get formats and modifiers */
@@ -1791,7 +1817,7 @@ wsi_wl_surface_create_swapchain(VkIcdSurfaceBase *icd_surface,
    } else {
       drm_image_params = (struct wsi_drm_image_params) {
          .base.image_type = WSI_IMAGE_TYPE_DRM,
-         .same_gpu = true,
+         .same_gpu = wsi_wl_surface->display->same_gpu,
       };
       /* Use explicit DRM format modifiers when both the server and the driver
        * support them.