diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index eb5dcd84fea7aa22d48cc581dc5cfab1644e702c..9b0df08836c3aeb48b31efb15eb1913fc92db08e 100644
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -947,10 +947,18 @@ int drm_atomic_helper_check(struct drm_device *dev,
if (ret)
return ret;
+ /*
+ * If amend was explicitly requested, but it is not possible,
+ * return error instead of falling back to a normal commit.
+ */
+ if (state->amend_update)
+ return drm_atomic_helper_amend_check(dev, state);
+
+ /* Legacy mode falls back to a normal commit if amend isn't possible. */
if (state->legacy_cursor_update)
state->amend_update = !drm_atomic_helper_amend_check(dev, state);
- return ret;
+ return 0;
}
EXPORT_SYMBOL(drm_atomic_helper_check);
@@ -1574,12 +1582,20 @@ static void commit_work(struct work_struct *work)
* The amend feature provides a way to perform 1000 updates to be applied as
* soon as possible without waiting for 1000 vblanks.
- * Currently, only the legacy cursor update uses amend mode, where historically,
+ * Legacy cursor update uses amend mode, where historically,
* userspace performs several updates before the next vblank and don't want to
* see a delay in the cursor's movement.
* If amend is not supported, legacy cursor falls back to a normal sync update.
*
- * To implement the legacy cursor update, drivers should provide
+ * Amend can also be performed through the atomic API using the flag
+ * DRM_MODE_ATOMIC_AMEND. The atomic commit will fail if this flag is set but
+ * the driver doesn't support it.
+ * Amend can't perform modeset, thus atomic API will fail if
+ * DRM_MODE_ATOMIC_AMEND is used in conjunction with
+ * DRM_MODE_ATOMIC_ALLOW_MODESET flag.
+ *
+ * To implement the legacy cursor update and amend mode through atomic, drivers
+ * should provide:
* &drm_plane_helper_funcs.atomic_amend_check() and
* &drm_plane_helper_funcs.atomic_amend_update()
*
@@ -1601,16 +1617,21 @@ static void commit_work(struct work_struct *work)
*
* Notes / highlights:
*
- * - amend update is performed on legacy cursor updates.
+ * - amend update is performed on legacy cursor updates, but it will fallback to
+ * a normal commit if amend is not possible. However, if amend was requested
+ * through atomic, the ioctl will fail instead of fall back if it can't be
+ * amended.
+ *
+ * - atomic api will reject amend if DRM_MODE_ATOMIC_ALLOW_MODESET flag is used.
+ *
+ * - If DRM_MODE_PAGE_FLIP_ASYNC is set, then the DRM_MODE_ATOMIC_AMEND flag
+ * will be ignored.
*
* - amend update won't happen if there is an outstanding commit modifying the
* same plane.
*
* - amend update won't happen if atomic_amend_check() returns false.
*
- * - if atomic_amend_check() fails, it falls back to a normal synchronous
- * update.
- *
* - if userspace wants to ensure an asynchronous page flip, i.e. change hw
* state immediately, see DRM_MODE_PAGE_FLIP_ASYNC flag
* (asynchronous page flip maintains the amend property by definition).
@@ -1673,6 +1694,10 @@ int drm_atomic_helper_amend_check(struct drm_device *dev,
if (new_plane_state->fence)
return -EINVAL;
+ /* Only allow amend update for cursor type planes. */
+ if (plane->type != DRM_PLANE_TYPE_CURSOR)
+ return -EINVAL;
+
/*
* Don't do an amend update if there is an outstanding commit modifying
* the plane.
diff --git a/drivers/gpu/drm/drm_atomic_uapi.c b/drivers/gpu/drm/drm_atomic_uapi.c
index 4eb81f10bc54fcedbbe94420c53572b3269410a5..d1962cdea60292d5298f8779b91e7c81b45d8668 100644
--- a/drivers/gpu/drm/drm_atomic_uapi.c
+++ b/drivers/gpu/drm/drm_atomic_uapi.c
@@ -28,6 +28,7 @@
#include <drm/drm_atomic_uapi.h>
#include <drm/drm_atomic.h>
+#include <drm/drm_atomic_uapi.h>
#include <drm/drm_print.h>
#include <drm/drm_drv.h>
#include <drm/drm_writeback.h>
@@ -1300,6 +1301,10 @@ int drm_mode_atomic_ioctl(struct drm_device *dev,
(arg->flags & DRM_MODE_PAGE_FLIP_EVENT))
return -EINVAL;
+ if ((arg->flags & DRM_MODE_ATOMIC_ALLOW_MODESET) &&
+ (arg->flags & DRM_MODE_ATOMIC_AMEND))
+ return -EINVAL;
+
state = drm_atomic_state_alloc(dev);
if (!state)
return -ENOMEM;
@@ -1307,6 +1312,9 @@ int drm_mode_atomic_ioctl(struct drm_device *dev,
drm_modeset_acquire_init(&ctx, DRM_MODESET_ACQUIRE_INTERRUPTIBLE);
state->acquire_ctx = &ctx;
state->allow_modeset = !!(arg->flags & DRM_MODE_ATOMIC_ALLOW_MODESET);
+ /* async takes precedence over amend */
+ state->amend_update = arg->flags & DRM_MODE_PAGE_FLIP_ASYNC ? 0 :
+ !!(arg->flags & DRM_MODE_ATOMIC_AMEND);
retry:
copied_objs = 0;
diff --git a/include/uapi/drm/drm_mode.h b/include/uapi/drm/drm_mode.h
index 88ef2cf04d13935b9163deb85ea949d07f57142f..3831d04f3b38ef63048f41e4dee1280067d8052b 100644
--- a/include/uapi/drm/drm_mode.h
+++ b/include/uapi/drm/drm_mode.h
@@ -743,19 +743,26 @@ struct drm_mode_destroy_dumb {
*
* DRM_MODE_ATOMIC_ALLOW_MODESET
* Indicates whether a full modeset is acceptable or not.
+ *
+ * DRM_MODE_ATOMIC_AMEND
+ * Used to perform an atomic amend. See "DOC: amend mode atomic commit" in
+ * drm_atomic_helper.c for more details.
+ * This flag can't be used with DRM_MODE_ATOMIC_ALLOW_MODESET.
*/
/* */
#define DRM_MODE_ATOMIC_TEST_ONLY 0x0100
#define DRM_MODE_ATOMIC_NONBLOCK 0x0200
#define DRM_MODE_ATOMIC_ALLOW_MODESET 0x0400
+#define DRM_MODE_ATOMIC_AMEND 0x0800
#define DRM_MODE_ATOMIC_FLAGS (\
DRM_MODE_PAGE_FLIP_EVENT |\
DRM_MODE_PAGE_FLIP_ASYNC |\
DRM_MODE_ATOMIC_TEST_ONLY |\
DRM_MODE_ATOMIC_NONBLOCK |\
- DRM_MODE_ATOMIC_ALLOW_MODESET)
+ DRM_MODE_ATOMIC_ALLOW_MODESET |\
+ DRM_MODE_ATOMIC_AMEND)
struct drm_mode_atomic {
__u32 flags;