drm: Advertise async page flip ability through GETCAP ioctl

Let applications know whether the kernel supports asynchronous page
flipping.

Signed-off-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Dave Airlie <airlied@gmail.com>

4 files changed, 10 insertions, 0 deletions

diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index 4f35be732b83..452591b67996 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -3508,6 +3508,9 @@ int drm_mode_page_flip_ioctl(struct drm_device *dev,
             page_flip->reserved != 0)
                 return -EINVAL;
 
+        if ((page_flip->flags & DRM_MODE_PAGE_FLIP_ASYNC) && !dev->mode_config.async_page_flip)
+                return -EINVAL;
+
         obj = drm_mode_object_find(dev, page_flip->crtc_id, DRM_MODE_OBJECT_CRTC);
         if (!obj)
                 return -EINVAL;
diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c
index cffc7c0e1171..07247e2855a2 100644
--- a/drivers/gpu/drm/drm_ioctl.c
+++ b/drivers/gpu/drm/drm_ioctl.c
@@ -293,6 +293,9 @@ int drm_getcap(struct drm_device *dev, void *data, struct drm_file *file_priv)
         case DRM_CAP_TIMESTAMP_MONOTONIC:
                 req->value = drm_timestamp_monotonic;
                 break;
+        case DRM_CAP_ASYNC_PAGE_FLIP:
+                req->value = dev->mode_config.async_page_flip;
+                break;
         default:
                 return -EINVAL;
         }
diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
index 0c7fec5b8fef..78ca1512c73f 100644
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -842,6 +842,9 @@ struct drm_mode_config {
 
         /* dumb ioctl parameters */
         uint32_t preferred_depth, prefer_shadow;
+
+        /* whether async page flip is supported or not */
+        bool async_page_flip;
 };
 
 #define obj_to_crtc(x) container_of(x, struct drm_crtc, base)
diff --git a/include/uapi/drm/drm.h b/include/uapi/drm/drm.h
index 272580ca320f..ece867889cc7 100644
--- a/include/uapi/drm/drm.h
+++ b/include/uapi/drm/drm.h
@@ -780,6 +780,7 @@ struct drm_event_vblank {
 #define DRM_CAP_DUMB_PREFER_SHADOW 0x4
 #define DRM_CAP_PRIME 0x5
 #define DRM_CAP_TIMESTAMP_MONOTONIC 0x6
+#define DRM_CAP_ASYNC_PAGE_FLIP 0x7
 
 #define DRM_PRIME_CAP_IMPORT 0x1
 #define DRM_PRIME_CAP_EXPORT 0x2