[PATCH 2/5] drm: use page-flip for sprites, in case no vblank event

[David Herrmann]

Hi Rob

On Mon, Mar 12, 2012 at 1:48 AM, Rob Clark <rob.clark at linaro.org> wrote:
> From: Rob Clark <rob at ti.com>
>
> If the output does not support vblank events (possibly the case with
> USB or DSI command mode displays which do not have a traditional
> vsync), use instead the page_flip handler to know when the display
> is finished scanning out a sprite.
> ---
>  src/compositor-drm.c |   17 +++++++++++++++--
>  1 files changed, 15 insertions(+), 2 deletions(-)
>
> diff --git a/src/compositor-drm.c b/src/compositor-drm.c
> index 67fa500..500ec15 100644
> --- a/src/compositor-drm.c
> +++ b/src/compositor-drm.c
> @@ -117,6 +117,12 @@ struct drm_sprite {
>        uint32_t dest_x, dest_y;
>        uint32_t dest_w, dest_h;
>
> +       /*
> +        * for displays that don't have a vblank (dsi command-mode displays,
> +        * usb displays, etc), it can be simulated from the page-flip event
> +        */
> +       int simulate_vblank;
> +
>        uint32_t formats[];
>  };
>
> @@ -286,8 +292,7 @@ drm_output_repaint(struct weston_output *output_base,
>                vbl.request.signal = (unsigned long)s;
>                ret = drmWaitVBlank(compositor->drm.fd, &vbl);
>                if (ret) {
> -                       fprintf(stderr, "vblank event request failed: %d: %s\n",
> -                               ret, strerror(errno));
> +                       s->simulate_vblank = 1;
>                }

Doesn't it make sense to add an:
if (!s->simulate_vblank)
around this drmWaitVBlank call? Otherwise we try it at every repaint
and it will fail everytime.

Regards
David

>        }
>
> @@ -327,6 +332,7 @@ page_flip_handler(int fd, unsigned int frame,
>        struct drm_output *output = (struct drm_output *) data;
>        struct drm_compositor *c =
>                (struct drm_compositor *) output->base.compositor;
> +       struct drm_sprite *s;
>        uint32_t msecs;
>
>        if (output->scanout_buffer) {
> @@ -349,6 +355,13 @@ page_flip_handler(int fd, unsigned int frame,
>
>        msecs = sec * 1000 + usec / 1000;
>        weston_output_finish_frame(&output->base, msecs);
> +
> +       wl_list_for_each(s, &c->sprite_list, link) {
> +               if (s->simulate_vblank) {
> +                       vblank_handler(fd, frame, sec, usec, s);
> +                       s->simulate_vblank = 0;
> +               }
> +       }
>  }
>
>  static int
> --
> 1.7.5.4
>
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