drm/amdgpu/display: Only set vblank_disable_immediate when PSR is not enabled

[Why]
PSR currently relies on the kernel's delayed vblank on/off mechanism
as an implicit bufferring mechanism to prevent excessive entry/exit.

Without this delay the user experience is impacted since it can take
a few frames to enter/exit.

[How]
Only allow vblank disable immediate for DC when psr is not supported.

Leave a TODO indicating that this support should be extended in the
future to delay independent of the vblank interrupt.

Fixes: 92020e81 ("drm/amdgpu/display: set vblank_disable_immediate for DC")
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c

@@ -1599,9 +1599,6 @@ static int amdgpu_dm_init(struct amdgpu_device *adev)
 	adev_to_drm(adev)->mode_config.cursor_width = adev->dm.dc->caps.max_cursor_size;
 	adev_to_drm(adev)->mode_config.cursor_height = adev->dm.dc->caps.max_cursor_size;
 
-	/* Disable vblank IRQs aggressively for power-saving */
-	adev_to_drm(adev)->vblank_disable_immediate = true;
-
 	if (drm_vblank_init(adev_to_drm(adev), adev->dm.display_indexes_num)) {
 		DRM_ERROR(
 		"amdgpu: failed to initialize sw for display support.\n");
@@ -4264,6 +4261,14 @@ static int amdgpu_dm_initialize_drm_device(struct amdgpu_device *adev)
 
 	}
 
+	/*
+	 * Disable vblank IRQs aggressively for power-saving.
+	 *
+	 * TODO: Fix vblank control helpers to delay PSR entry to allow this when PSR
+	 * is also supported.
+	 */
+	adev_to_drm(adev)->vblank_disable_immediate = !psr_feature_enabled;
+
 	/* Software is initialized. Now we can register interrupt handlers. */
 	switch (adev->asic_type) {
 #if defined(CONFIG_DRM_AMD_DC_SI)