drm/nouveau: Call drm_vblank_pre/post_modeset() around mode setting.

Signed-off-by: Francisco Jerez <currojerez@riseup.net>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/nv04_crtc.c

@@ -672,6 +672,7 @@ static void nv_crtc_prepare(struct drm_crtc *crtc)
 	if (nv_two_heads(dev))
 		NVSetOwner(dev, nv_crtc->index);
 
+	drm_vblank_pre_modeset(dev, nv_crtc->index);
 	funcs->dpms(crtc, DRM_MODE_DPMS_OFF);
 
 	NVBlankScreen(dev, nv_crtc->index, true);
@@ -704,6 +705,7 @@ static void nv_crtc_commit(struct drm_crtc *crtc)
 #endif
 
 	funcs->dpms(crtc, DRM_MODE_DPMS_ON);
+	drm_vblank_post_modeset(dev, nv_crtc->index);
 }
 
 static void nv_crtc_destroy(struct drm_crtc *crtc)

drivers/gpu/drm/nouveau/nv50_crtc.c

@@ -454,6 +454,7 @@ nv50_crtc_prepare(struct drm_crtc *crtc)
 
 	NV_DEBUG_KMS(dev, "index %d\n", nv_crtc->index);
 
+	drm_vblank_pre_modeset(dev, nv_crtc->index);
 	nv50_crtc_blank(nv_crtc, true);
 }
 
@@ -469,6 +470,7 @@ nv50_crtc_commit(struct drm_crtc *crtc)
 	NV_DEBUG_KMS(dev, "index %d\n", nv_crtc->index);
 
 	nv50_crtc_blank(nv_crtc, false);
+	drm_vblank_post_modeset(dev, nv_crtc->index);
 
 	ret = RING_SPACE(evo, 2);
 	if (ret) {