[2/2] drm/virtio: send vblank event on plane atomic update

Commit Message

Gustavo Padovan March 21, 2016, 7:23 p.m. UTC

From: Gustavo Padovan <[e-mail]>

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 <[e-mail]>
---
 drivers/gpu/drm/virtio/virtgpu_plane.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

Comments

Daniel Stone March 22, 2016, 1:17 p.m. UTC | #1

Hi,

On 21 March 2016 at 19:23, Gustavo Padovan <[e-mail]> wrote:
> @@ -96,6 +98,11 @@ static void virtio_gpu_plane_atomic_update(struct drm_plane *plane,
>                                       plane->state->crtc_y,
>                                       plane->state->crtc_w,
>                                       plane->state->crtc_h);
> +
> +       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);

This seems like the wrong place to do it, in that it will generate one
flip event per plane, rather than one per CRTC. So this should
probably be done in the overall atomic_commit hook I think.

Also, without some kind of delay, this means that we'll generate
flip-complete events immediately, which will cause compositors like
Weston to render infinitely fast. It's probably worth looking at what
happened when this came up with Bochs - I'm not sure if we fake a 16ms
delay, or refuse to do async modesets, or what.

Cheers,
Daniel

Patch

diff --git a/drivers/gpu/drm/virtio/virtgpu_plane.c b/drivers/gpu/drm/virtio/virtgpu_plane.c
index 70b44a2..20260ad 100644
--- a/drivers/gpu/drm/virtio/virtgpu_plane.c
+++ b/drivers/gpu/drm/virtio/virtgpu_plane.c
@@ -63,9 +63,11 @@  static void virtio_gpu_plane_atomic_update(struct drm_plane *plane,
 {
 	struct drm_device *dev = plane->dev;
 	struct virtio_gpu_device *vgdev = dev->dev_private;
-	struct virtio_gpu_output *output = drm_crtc_to_virtio_gpu_output(plane->crtc);
+	struct drm_crtc *crtc = plane->crtc;
+	struct virtio_gpu_output *output = drm_crtc_to_virtio_gpu_output(crtc);
 	struct virtio_gpu_framebuffer *vgfb;
 	struct virtio_gpu_object *bo;
+	unsigned long flags;
 	uint32_t handle;
 
 	if (plane->state->fb) {
@@ -96,6 +98,11 @@  static void virtio_gpu_plane_atomic_update(struct drm_plane *plane,
 				      plane->state->crtc_y,
 				      plane->state->crtc_w,
 				      plane->state->crtc_h);
+
+	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);
 }