Re: [PATCH v5 1/4] drm/fence: add in-fences support

On Thu, Oct 20, 2016 at 12:50:02PM -0200, Gustavo Padovan wrote:

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

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

The fd is then translated to a fence (that may be a fence_collection 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

Signed-off-by: Gustavo Padovan gustavo.padovan@collabora.co.uk

Since you rename plane_state->fence to in_fence (why exactly?) this breaks compilation for imx and msm. Also there's the question of which fence should win, if there's both explicit and implicit fences. I think the best way to solve that is by adding a helper to set the implicit fence, which drivers are supposed to call. That helper only sets the fence if there's not yet an explicit fence attached. New sequence would be:

- patch1: roll out that helper (e.g. drm_atomic_plane_state_set_fence or whatever) for all drivers using it. - patch2 (this one here): add explicit fences and change the helper to cooporate correctly.

---

drivers/gpu/drm/Kconfig | 1 + drivers/gpu/drm/drm_atomic.c | 14 ++++++++++++++ drivers/gpu/drm/drm_atomic_helper.c | 13 +++++++------ drivers/gpu/drm/drm_crtc.c | 6 ++++++ drivers/gpu/drm/drm_plane.c | 1 + include/drm/drm_crtc.h | 5 +++++ include/drm/drm_plane.h | 4 ++-- 7 files changed, 36 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig index 483059a..43cb33d 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 5dd7054..b3284b2 100644 --- a/drivers/gpu/drm/drm_atomic.c +++ b/drivers/gpu/drm/drm_atomic.c @@ -30,6 +30,7 @@ #include <drm/drm_atomic.h> #include <drm/drm_mode.h> #include <drm/drm_plane_helper.h> +#include <linux/sync_file.h>

#include "drm_crtc_internal.h"

@@ -686,6 +687,17 @@ 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 (U642I64(val) == -1)
  

• 	return 0;
  

• if (state->in_fence)
  

• 	fence_put(state->in_fence);
  

• state->in_fence = sync_file_get_fence(val);
  

• if (!state->in_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);

@@ -745,6 +757,8 @@ 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 07b432f..73464b1 100644 --- a/drivers/gpu/drm/drm_atomic_helper.c +++ b/drivers/gpu/drm/drm_atomic_helper.c @@ -1031,22 +1031,20 @@ int drm_atomic_helper_wait_for_fences(struct drm_device *dev, if (!pre_swap) plane_state = plane->state;

• if (!plane_state->fence)
  

• if (!plane_state->in_fence)
  continue;
  
  

• WARN_ON(!plane_state->fb);
  

• /*
  • If waiting for fences pre-swap (ie: nonblock), userspace can
  • still interrupt the operation. Instead of blocking until the
  • timer expires, make the wait interruptible.
  */

• ret = fence_wait(plane_state->fence, pre_swap);
  

• ret = fence_wait(plane_state->in_fence, pre_swap);
  

  if (ret) return ret;

• fence_put(plane_state->fence);
  

• plane_state->fence = NULL;
  

• fence_put(plane_state->in_fence);
  

• plane_state->in_fence = NULL;
  

  }

  return 0;

@@ -3114,6 +3112,9 @@ void __drm_atomic_helper_plane_destroy_state(struct drm_plane_state *state) { if (state->fb) drm_framebuffer_unreference(state->fb);

• if (state->in_fence)

• fence_put(state->in_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 60403bf..fcb6453 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 284c1b3..279132e 100644 --- a/include/drm/drm_crtc.h +++ b/include/drm/drm_crtc.h @@ -1206,6 +1206,11 @@ 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.
  */

diff --git a/include/drm/drm_plane.h b/include/drm/drm_plane.h index 0235390..3cb9bf1 100644 --- a/include/drm/drm_plane.h +++ b/include/drm/drm_plane.h @@ -34,7 +34,7 @@ struct drm_crtc;

• @plane: backpointer to the plane
• @crtc: currently bound CRTC, NULL if disabled
• @fb: currently bound framebuffer

• • @fence: optional fence to wait for before scanning out @fb

• • @in_fence: optional fence to wait for before scanning out @fb
  • @crtc_x: left position of visible portion of plane on crtc
  • @crtc_y: upper position of visible portion of plane on crtc
  • @crtc_w: width of visible portion of plane on crtc

@@ -59,7 +59,7 @@ struct drm_plane_state {

struct drm_crtc *crtc; /* do not write directly, use drm_atomic_set_crtc_for_plane() */ struct drm_framebuffer *fb; /* do not write directly, use drm_atomic_set_fb_for_plane() */

• struct fence *fence;

• struct fence *in_fence;

I think it'd be good to move the kerneldoc into an in-line comment here and expand a bit upon the expected semantics. This is a pretty important part of the atomic uabi!

Otherwise looks all good. -Daniel

/* Signed dest location allows it to be partially off screen */ int32_t crtc_x, crtc_y; -- 2.5.5