On Tue, Apr 04, 2017 at 05:52:21PM +0100, Daniel Stone wrote:
> From: Ander Conselvan de Oliveira <ander.conselvan.de.oliveira@xxxxxxxxx>
>
> With the atomic API, it is possible that a single commit affects
> multiple crtcs. If the user requests an event with that commit, one
> event will be sent for each CRTC, but it is not possible to distinguish
> which crtc an event is for in user space. To solve this, the reserved
> field in struct drm_vblank_event is repurposed to include the crtc_id
> which the event is for.
>
> The DRM_CAP_CRTC_IN_VBLANK_EVENT is added to allow userspace to query if
> the crtc field will be set properly.
>
> [daniels: Rebased, using Maarten's forward-port.]
>
> Signed-off-by: Ander Conselvan de Oliveira <ander.conselvan.de.oliveira@xxxxxxxxx>
> Signed-off-by: Daniel Stone <daniels@xxxxxxxxxxxxx>
Yeah, this seems like good use of the reserved field to me.
Reviewed-by: Sean Paul <seanpaul@xxxxxxxxxxxx>
> Cc: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxx>
> ---
> drivers/gpu/drm/drm_ioctl.c | 3 +++
> drivers/gpu/drm/drm_irq.c | 2 ++
> include/uapi/drm/drm.h | 3 ++-
> 3 files changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c
> index 7d6deaa91281..0793e2da9d21 100644
> --- a/drivers/gpu/drm/drm_ioctl.c
> +++ b/drivers/gpu/drm/drm_ioctl.c
> @@ -286,6 +286,9 @@ static int drm_getcap(struct drm_device *dev, void *data, struct drm_file *file_
> case DRM_CAP_ADDFB2_MODIFIERS:
> req->value = dev->mode_config.allow_fb_modifiers;
> break;
> + case DRM_CAP_CRTC_IN_VBLANK_EVENT:
> + req->value = 1;
> + break;
> default:
> return -EINVAL;
> }
> diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c
> index dac1b2593cb1..8c866cac62dd 100644
> --- a/drivers/gpu/drm/drm_irq.c
> +++ b/drivers/gpu/drm/drm_irq.c
> @@ -1026,6 +1026,7 @@ void drm_crtc_arm_vblank_event(struct drm_crtc *crtc,
>
> e->pipe = pipe;
> e->event.sequence = drm_vblank_count(dev, pipe);
> + e->event.crtc_id = crtc->base.id;
> list_add_tail(&e->base.link, &dev->vblank_event_list);
> }
> EXPORT_SYMBOL(drm_crtc_arm_vblank_event);
> @@ -1056,6 +1057,7 @@ void drm_crtc_send_vblank_event(struct drm_crtc *crtc,
> now = get_drm_timestamp();
> }
> e->pipe = pipe;
> + e->event.crtc_id = crtc->base.id;
> send_vblank_event(dev, e, seq, &now);
> }
> EXPORT_SYMBOL(drm_crtc_send_vblank_event);
> diff --git a/include/uapi/drm/drm.h b/include/uapi/drm/drm.h
> index b2c52843bc70..42d9f64ce416 100644
> --- a/include/uapi/drm/drm.h
> +++ b/include/uapi/drm/drm.h
> @@ -647,6 +647,7 @@ struct drm_gem_open {
> #define DRM_CAP_CURSOR_HEIGHT 0x9
> #define DRM_CAP_ADDFB2_MODIFIERS 0x10
> #define DRM_CAP_PAGE_FLIP_TARGET 0x11
> +#define DRM_CAP_CRTC_IN_VBLANK_EVENT 0x12
>
> /** DRM_IOCTL_GET_CAP ioctl argument type */
> struct drm_get_cap {
> @@ -851,7 +852,7 @@ struct drm_event_vblank {
> __u32 tv_sec;
> __u32 tv_usec;
> __u32 sequence;
> - __u32 reserved;
> + __u32 crtc_id; /* 0 on older kernels that do not support this */
> };
>
> /* typedef area */
> --
> 2.11.0
>
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--
Sean Paul, Software Engineer, Google / Chromium OS
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