radv: set RADEON_FLAG_GTT_WC flag for prime memory

With display on iGPU and render on dGPU, VRR is not working. To fix
this set RADEON_FLAG_GTT_WC flag when allocating memory for prime. This
allows kernel function amdgpu_display_user_framebuffer_create() to
allocate GTT memory with USWC flag making the buffer scanout for iGPU.
This helps the ddx amdgpu_present_check_flip() function to return
true. Now, xserver will flip the framebuffer instead of blit. Due
to this VRR feature will work where iGPU supports USWC flag.

v2: modify commit message with use case (Michel Dänzer)
v3: allow GTT_WC flag only if VRAM_DOMAIN and NO_CPU_ACCESS (Bas Nieuwenhuizen)
v4: add check for wsi_info is NULL
v5: use wsi_info pointer to check for prime alloc (Bas Nieuwenhuizen)
v6: set _GTT_WC flag when wsi_info pointer is not NULL (Bas Nieuwenhuizen)

Signed-off-by: Yogesh Mohanmarimuthu <yogesh.mohanmarimuthu@amd.com>
Signed-off-by: Vitaly Prosyak <vitaly.prosyak@amd.com>
Reviewed-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/10657>

diff --git a/src/amd/vulkan/radv_device.c b/src/amd/vulkan/radv_device.c
index 38de336..0ab8ee2 100644 (file)
--- a/src/amd/vulkan/radv_device.c
+++ b/src/amd/vulkan/radv_device.c
@@ -5180,8 +5180,20 @@ radv_alloc_memory(struct radv_device *device, const VkMemoryAllocateInfo *pAlloc
 
    vk_object_base_init(&device->vk, &mem->base, VK_OBJECT_TYPE_DEVICE_MEMORY);
 
-   if (wsi_info && wsi_info->implicit_sync)
-      flags |= RADEON_FLAG_IMPLICIT_SYNC;
+   if (wsi_info) {
+      if(wsi_info->implicit_sync)
+         flags |= RADEON_FLAG_IMPLICIT_SYNC;
+
+      /* In case of prime, linear buffer is allocated in default heap which is VRAM.
+       * Due to this when display is connected to iGPU and render on dGPU, ddx
+       * function amdgpu_present_check_flip() fails due to which there is blit
+       * instead of flip. Setting the flag RADEON_FLAG_GTT_WC allows kernel to
+       * allocate GTT memory in supported hardware where GTT can be directly scanout.
+       * Using wsi_info variable check to set the flag RADEON_FLAG_GTT_WC so that
+       * only for memory allocated by driver this flag is set.
+       */
+      flags |= RADEON_FLAG_GTT_WC;
+   }
 
    if (dedicate_info) {
       mem->image = radv_image_from_handle(dedicate_info->image);