[PATCH v8 1/3] drm/fence: add in-fences support

Gustavo Padovan
2016-11-11T05:16:29Z

From: Gustavo Padovan <gustavo.padovan@collabora.co.uk>

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

Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
---
drivers/gpu/drm/Kconfig | 1 +
drivers/gpu/drm/drm_atomic.c | 14 ++++++++++++++
drivers/gpu/drm/drm_atomic_helper.c | 5 +++++
drivers/gpu/drm/drm_crtc.c | 6 ++++++
drivers/gpu/drm/drm_plane.c | 1 +
include/drm/drm_crtc.h | 5 +++++
6 files changed, 32 insertions(+)

diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index 25e8e37..360cb92 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -12,6 +12,7 @@ menuconfig DRM
select I2C
select I2C_ALGOBIT
select DMA_SHARED_BUFFER
+ select SYNC_FILE
help
Kernel-level support for the Direct Rendering Infrastructure (DRI)
introduced in XFree86 4.0. If you say Y here, you need to select
diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
index b096c16..8e26ad1 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"

@@ -709,6 +710,17 @@ 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);
@@ -770,6 +782,8 @@ 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) {
diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index 75ad01d..caed870 100644
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -3076,6 +3076,8 @@ void __drm_atomic_helper_plane_duplicate_state(struct drm_plane *plane,

if (state->fb)
drm_framebuffer_reference(state->fb);
+
+ state->fence = NULL;
}
EXPORT_SYMBOL(__drm_atomic_helper_plane_duplicate_state);

@@ -3114,6 +3116,9 @@ void __drm_atomic_helper_plane_destroy_state(struct drm_plane_state *state)
{
if (state->fb)
drm_framebuffer_unreference(state->fb);
+
+ if (state->fence)
+ dma_fence_put(state->fence);
}
EXPORT_SYMBOL(__drm_atomic_helper_plane_destroy_state);

diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index ce274ed..154e040 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -397,6 +397,12 @@ static int drm_mode_create_standard_properties(struct drm_device *dev)
return -ENOMEM;
dev->mode_config.prop_fb_id = prop;

+ prop = drm_property_create_signed_range(dev, DRM_MODE_PROP_ATOMIC,
+ "IN_FENCE_FD", -1, INT_MAX);
+ if (!prop)
+ return -ENOMEM;
+ dev->mode_config.prop_in_fence_fd = prop;
+
prop = drm_property_create_object(dev, DRM_MODE_PROP_ATOMIC,
"CRTC_ID", DRM_MODE_OBJECT_CRTC);
if (!prop)
diff --git a/drivers/gpu/drm/drm_plane.c b/drivers/gpu/drm/drm_plane.c
index 249c0ae..3957ef8 100644
--- a/drivers/gpu/drm/drm_plane.c
+++ b/drivers/gpu/drm/drm_plane.c
@@ -137,6 +137,7 @@ int drm_universal_plane_init(struct drm_device *dev, struct drm_plane *plane,

if (drm_core_check_feature(dev, DRIVER_ATOMIC)) {
drm_object_attach_property(&plane->base, config->prop_fb_id, 0);
+ drm_object_attach_property(&plane->base, config->prop_in_fence_fd, -1);
drm_object_attach_property(&plane->base, config->prop_crtc_id, 0);
drm_object_attach_property(&plane->base, config->prop_crtc_x, 0);
drm_object_attach_property(&plane->base, config->prop_crtc_y, 0);
diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
index 8cca2a8..11780a9 100644
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -1214,6 +1214,11 @@ struct drm_mode_config {
*/
struct drm_property *prop_fb_id;
/**
+ * @prop_in_fence_fd: Sync File fd representing the incoming fences
+ * for a Plane.
+ */
+ struct drm_property *prop_in_fence_fd;
+ /**
* @prop_crtc_id: Default atomic plane property to specify the
* &drm_crtc.
*/
--
2.5.5