drm/fence: add in-fences support

There is now a new property called IN_FENCE_FD attached to every plane
state that receives sync_file fds from userspace via the atomic commit
IOCTL.

The fd is then translated to a fence (that may be a fence_array
subclass or just a normal fence) and then used by DRM to fence_wait() for
all fences in the sync_file to signal. So it only commits when all
framebuffers are ready to scanout.

v2: Comments by Daniel Vetter:
	- remove set state->fence = NULL in destroy phase
	- accept fence -1 as valid and just return 0
	- do not call fence_get() - sync_file_fences_get() already calls it
	- fence_put() if state->fence is already set, in case userspace
	set the property more than once.

v3: WARN_ON if fence is set but state has no FB

v4: Comment from Maarten Lankhorst
	- allow set fence with no related fb

v5: rename FENCE_FD to IN_FENCE_FD

v6: Comments by Daniel Vetter:
	- rename plane_state->in_fence back to "fence"
	- re-introduce WARN_ON if fence set but no fb

     - rebase after fence -> dma_fence rename

v7: Comments by Brian Starkey
	- set state->fence to NULL when duplicating the state
	- fail if IN_FENCE_FD was already set

v8: rebase against latest drm-misc

Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Reviewed-by: Brian Starkey <brian.starkey@arm.com>
Reviewed-by: Sean Paul <seanpaul@chromium.org>
Tested-by: Robert Foss <robert.foss@collabora.com>
[danvet: Rebase onto extracted drm_mode_config.[hc].]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 14 insertions, 0 deletions

diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
index 57e0a6e96f6d..3ad780ad24f9 100644
--- a/drivers/gpu/drm/drm_atomic.c
+++ b/drivers/gpu/drm/drm_atomic.c
@@ -31,6 +31,7 @@
 #include <drm/drm_mode.h>
 #include <drm/drm_plane_helper.h>
 #include <drm/drm_print.h>
+#include <linux/sync_file.h>
 
 #include "drm_crtc_internal.h"
 
@@ -712,6 +713,17 @@ int drm_atomic_plane_set_property(struct drm_plane *plane,
 		drm_atomic_set_fb_for_plane(state, fb);
 		if (fb)
 			drm_framebuffer_unreference(fb);
+	} else if (property == config->prop_in_fence_fd) {
+		if (state->fence)
+			return -EINVAL;
+
+		if (U642I64(val) == -1)
+			return 0;
+
+		state->fence = sync_file_get_fence(val);
+		if (!state->fence)
+			return -EINVAL;
+
 	} else if (property == config->prop_crtc_id) {
 		struct drm_crtc *crtc = drm_crtc_find(dev, val);
 		return drm_atomic_set_crtc_for_plane(state, crtc);
@@ -773,6 +785,8 @@ drm_atomic_plane_get_property(struct drm_plane *plane,
 
 	if (property == config->prop_fb_id) {
 		*val = (state->fb) ? state->fb->base.id : 0;
+	} else if (property == config->prop_in_fence_fd) {
+		*val = -1;
 	} else if (property == config->prop_crtc_id) {
 		*val = (state->crtc) ? state->crtc->base.id : 0;
 	} else if (property == config->prop_crtc_x) {