drm/amdgpu: restore the fbdev mode in lastclose

restore the fbdev state if a drm app like X is killed.
Reviewed-by: Michel Dänzer <michel.daenzer@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/amdgpu_fb.c

@@ -402,3 +402,19 @@ bool amdgpu_fbdev_robj_is_fb(struct amdgpu_device *adev, struct amdgpu_bo *robj)
 		return true;
 	return false;
 }
+
+void amdgpu_fbdev_restore_mode(struct amdgpu_device *adev)
+{
+	struct amdgpu_fbdev *afbdev = adev->mode_info.rfbdev;
+	struct drm_fb_helper *fb_helper;
+	int ret;
+
+	if (!afbdev)
+		return;
+
+	fb_helper = &afbdev->helper;
+
+	ret = drm_fb_helper_restore_fbdev_mode_unlocked(fb_helper);
+	if (ret)
+		DRM_DEBUG("failed to restore crtc mode\n");
+}

drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c

@@ -485,7 +485,7 @@ static int amdgpu_info_ioctl(struct drm_device *dev, void *data, struct drm_file
  * Outdated mess for old drm with Xorg being in charge (void function now).
  */
 /**
- * amdgpu_driver_firstopen_kms - drm callback for last close
+ * amdgpu_driver_lastclose_kms - drm callback for last close
  *
  * @dev: drm dev pointer
  *
@@ -493,6 +493,9 @@ static int amdgpu_info_ioctl(struct drm_device *dev, void *data, struct drm_file
  */
 void amdgpu_driver_lastclose_kms(struct drm_device *dev)
 {
+	struct amdgpu_device *adev = dev->dev_private;
+
+	amdgpu_fbdev_restore_mode(adev);
 	vga_switcheroo_process_delayed_switch();
 }
 

drivers/gpu/drm/amd/amdgpu/amdgpu_mode.h

@@ -567,6 +567,7 @@ void amdgpu_fbdev_fini(struct amdgpu_device *adev);
 void amdgpu_fbdev_set_suspend(struct amdgpu_device *adev, int state);
 int amdgpu_fbdev_total_size(struct amdgpu_device *adev);
 bool amdgpu_fbdev_robj_is_fb(struct amdgpu_device *adev, struct amdgpu_bo *robj);
+void amdgpu_fbdev_restore_mode(struct amdgpu_device *adev);
 
 void amdgpu_fb_output_poll_changed(struct amdgpu_device *adev);