drm/i915/gvt: add missing display part reset for vGPU reset

We also need reset vGPU virtual display emulation. Since all vreg has
been cleared, we need reset display related vreg to reflect our display
setting.
Signed-off-by: Changbin Du <changbin.du@intel.com>
Cc: Ping Gao <ping.a.gao@intel.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>

drivers/gpu/drm/i915/gvt/display.c

@@ -333,3 +333,15 @@ int intel_vgpu_init_display(struct intel_vgpu *vgpu)
 	else
 		return setup_virtual_dp_monitor(vgpu, PORT_B, GVT_DP_B);
 }
+
+/**
+ * intel_vgpu_reset_display- reset vGPU virtual display emulation
+ * @vgpu: a vGPU
+ *
+ * This function is used to reset vGPU virtual display emulation stuffs
+ *
+ */
+void intel_vgpu_reset_display(struct intel_vgpu *vgpu)
+{
+	emulate_monitor_status_change(vgpu);
+}

drivers/gpu/drm/i915/gvt/display.h

@@ -158,6 +158,7 @@ void intel_gvt_emulate_vblank(struct intel_gvt *gvt);
 void intel_gvt_check_vblank_emulation(struct intel_gvt *gvt);
 
 int intel_vgpu_init_display(struct intel_vgpu *vgpu);
+void intel_vgpu_reset_display(struct intel_vgpu *vgpu);
 void intel_vgpu_clean_display(struct intel_vgpu *vgpu);
 
 #endif

drivers/gpu/drm/i915/gvt/vgpu.c

@@ -385,6 +385,7 @@ void intel_gvt_reset_vgpu_locked(struct intel_vgpu *vgpu, bool dmlr,
 		intel_vgpu_reset_resource(vgpu);
 		intel_vgpu_reset_mmio(vgpu);
 		populate_pvinfo_page(vgpu);
+		intel_vgpu_reset_display(vgpu);
 
 		if (dmlr)
 			intel_vgpu_reset_cfg_space(vgpu);