FAILED: patch "[PATCH] drm/virtio: send vblank event after crtc updates" failed to apply to 4.5-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 4.5-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

>From 9a11d2e7e66b6b8764a2430686b8716637bf812e Mon Sep 17 00:00:00 2001
From: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Date: Thu, 14 Apr 2016 10:58:54 -0700
Subject: [PATCH] drm/virtio: send vblank event after crtc updates

virtio_gpu was failing to send vblank events when using the atomic IOCTL
with the DRM_MODE_PAGE_FLIP_EVENT flag set. This patch fixes each and
enables atomic pageflips updates.

Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Cc: stable@vger.kernel.org
Signed-off-by: Dave Airlie <airlied@redhat.com>

diff --git a/drivers/gpu/drm/virtio/virtgpu_display.c b/drivers/gpu/drm/virtio/virtgpu_display.c
index 4854dac87e24..5fd1fd06effc 100644
--- a/drivers/gpu/drm/virtio/virtgpu_display.c
+++ b/drivers/gpu/drm/virtio/virtgpu_display.c
@@ -267,11 +267,23 @@ static int virtio_gpu_crtc_atomic_check(struct drm_crtc *crtc,
 	return 0;
 }
 
+static void virtio_gpu_crtc_atomic_flush(struct drm_crtc *crtc,
+					 struct drm_crtc_state *old_state)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&crtc->dev->event_lock, flags);
+	if (crtc->state->event)
+		drm_crtc_send_vblank_event(crtc, crtc->state->event);
+	spin_unlock_irqrestore(&crtc->dev->event_lock, flags);
+}
+
 static const struct drm_crtc_helper_funcs virtio_gpu_crtc_helper_funcs = {
 	.enable        = virtio_gpu_crtc_enable,
 	.disable       = virtio_gpu_crtc_disable,
 	.mode_set_nofb = virtio_gpu_crtc_mode_set_nofb,
 	.atomic_check  = virtio_gpu_crtc_atomic_check,
+	.atomic_flush  = virtio_gpu_crtc_atomic_flush,
 };
 
 static void virtio_gpu_enc_mode_set(struct drm_encoder *encoder,