[Intel-gfx] [PATCH] drm/i915/display: Use dma_fence interfaces instead of i915_sw_fence

Jouni Högander jouni.hogander at intel.com
Mon Oct 16 08:08:03 UTC 2023


We are preparing for Xe driver. Xe driver doesn't have i915_sw_fence
implementation. Lets drop i915_sw_fence usage from display code and
use dma_fence interfaces directly.

For this purpose stack dma fences from related objects into old and new
plane states using drm_gem_plane_helper_prepare_fb. Then wait for these
stacked fences during atomic commit.

There is no be need for separate GPU reset handling in
intel_atomic_commit_fence_wait as the fences are signaled when GPU hang is
detected and GPU is being reset.

Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
Cc: José Roberto de Souza <jose.souza at intel.com>

Signed-off-by: Jouni Högander <jouni.hogander at intel.com>
---
 drivers/gpu/drm/i915/display/intel_atomic.c   |  3 -
 .../gpu/drm/i915/display/intel_atomic_plane.c | 49 +++---------
 drivers/gpu/drm/i915/display/intel_display.c  | 78 ++++++-------------
 .../drm/i915/display/intel_display_types.h    |  2 -
 4 files changed, 37 insertions(+), 95 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_atomic.c b/drivers/gpu/drm/i915/display/intel_atomic.c
index 5d18145da279..ec0d5168b503 100644
--- a/drivers/gpu/drm/i915/display/intel_atomic.c
+++ b/drivers/gpu/drm/i915/display/intel_atomic.c
@@ -331,9 +331,6 @@ void intel_atomic_state_free(struct drm_atomic_state *_state)
 
 	drm_atomic_state_default_release(&state->base);
 	kfree(state->global_objs);
-
-	i915_sw_fence_fini(&state->commit_ready);
-
 	kfree(state);
 }
 
diff --git a/drivers/gpu/drm/i915/display/intel_atomic_plane.c b/drivers/gpu/drm/i915/display/intel_atomic_plane.c
index b1074350616c..d4f9168ec42c 100644
--- a/drivers/gpu/drm/i915/display/intel_atomic_plane.c
+++ b/drivers/gpu/drm/i915/display/intel_atomic_plane.c
@@ -32,6 +32,7 @@
  */
 
 #include <drm/drm_atomic_helper.h>
+#include <drm/drm_gem_atomic_helper.h>
 #include <drm/drm_blend.h>
 #include <drm/drm_fourcc.h>
 
@@ -1035,7 +1036,7 @@ intel_prepare_plane_fb(struct drm_plane *_plane,
 	struct intel_atomic_state *state =
 		to_intel_atomic_state(new_plane_state->uapi.state);
 	struct drm_i915_private *dev_priv = to_i915(plane->base.dev);
-	const struct intel_plane_state *old_plane_state =
+	struct intel_plane_state *old_plane_state =
 		intel_atomic_get_old_plane_state(state, plane);
 	struct drm_i915_gem_object *obj = intel_fb_obj(new_plane_state->hw.fb);
 	struct drm_i915_gem_object *old_obj = intel_fb_obj(old_plane_state->hw.fb);
@@ -1057,56 +1058,30 @@ intel_prepare_plane_fb(struct drm_plane *_plane,
 		 * This should only fail upon a hung GPU, in which case we
 		 * can safely continue.
 		 */
-		if (new_crtc_state && intel_crtc_needs_modeset(new_crtc_state)) {
-			ret = i915_sw_fence_await_reservation(&state->commit_ready,
-							      old_obj->base.resv,
-							      false, 0,
-							      GFP_KERNEL);
+		if (new_crtc_state && intel_crtc_needs_modeset(new_crtc_state) &&
+		    !dma_resv_test_signaled(old_obj->base.resv,
+					    dma_resv_usage_rw(false))) {
+			ret = drm_gem_plane_helper_prepare_fb(_plane, &old_plane_state->uapi);
 			if (ret < 0)
 				return ret;
 		}
 	}
 
-	if (new_plane_state->uapi.fence) { /* explicit fencing */
-		i915_gem_fence_wait_priority(new_plane_state->uapi.fence,
-					     &attr);
-		ret = i915_sw_fence_await_dma_fence(&state->commit_ready,
-						    new_plane_state->uapi.fence,
-						    i915_fence_timeout(dev_priv),
-						    GFP_KERNEL);
-		if (ret < 0)
-			return ret;
-	}
-
 	if (!obj)
 		return 0;
 
-
 	ret = intel_plane_pin_fb(new_plane_state);
 	if (ret)
 		return ret;
 
-	i915_gem_object_wait_priority(obj, 0, &attr);
-
-	if (!new_plane_state->uapi.fence) { /* implicit fencing */
-		struct dma_resv_iter cursor;
-		struct dma_fence *fence;
+	ret = drm_gem_plane_helper_prepare_fb(_plane, &new_plane_state->uapi);
+	if (ret < 0)
+		goto unpin_fb;
 
-		ret = i915_sw_fence_await_reservation(&state->commit_ready,
-						      obj->base.resv, false,
-						      i915_fence_timeout(dev_priv),
-						      GFP_KERNEL);
-		if (ret < 0)
-			goto unpin_fb;
+	if (new_plane_state->uapi.fence) {
+		i915_gem_fence_wait_priority(new_plane_state->uapi.fence,
+					     &attr);
 
-		dma_resv_iter_begin(&cursor, obj->base.resv,
-				    DMA_RESV_USAGE_WRITE);
-		dma_resv_for_each_fence_unlocked(&cursor, fence) {
-			intel_display_rps_boost_after_vblank(new_plane_state->hw.crtc,
-							     fence);
-		}
-		dma_resv_iter_end(&cursor);
-	} else {
 		intel_display_rps_boost_after_vblank(new_plane_state->hw.crtc,
 						     new_plane_state->uapi.fence);
 	}
diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
index 28d85e1e858e..48df0559df00 100644
--- a/drivers/gpu/drm/i915/display/intel_display.c
+++ b/drivers/gpu/drm/i915/display/intel_display.c
@@ -48,6 +48,7 @@
 #include "g4x_dp.h"
 #include "g4x_hdmi.h"
 #include "hsw_ips.h"
+#include "i915_config.h"
 #include "i915_drv.h"
 #include "i915_reg.h"
 #include "i915_utils.h"
@@ -7056,29 +7057,34 @@ void intel_atomic_helper_free_state_worker(struct work_struct *work)
 
 static void intel_atomic_commit_fence_wait(struct intel_atomic_state *intel_state)
 {
-	struct wait_queue_entry wait_fence, wait_reset;
-	struct drm_i915_private *dev_priv = to_i915(intel_state->base.dev);
-
-	init_wait_entry(&wait_fence, 0);
-	init_wait_entry(&wait_reset, 0);
-	for (;;) {
-		prepare_to_wait(&intel_state->commit_ready.wait,
-				&wait_fence, TASK_UNINTERRUPTIBLE);
-		prepare_to_wait(bit_waitqueue(&to_gt(dev_priv)->reset.flags,
-					      I915_RESET_MODESET),
-				&wait_reset, TASK_UNINTERRUPTIBLE);
+	struct drm_i915_private *i915 = to_i915(intel_state->base.dev);
+	struct drm_plane *plane;
+	struct drm_plane_state *new_plane_state, *old_plane_state;
+	int ret, i;
 
+	for_each_oldnew_plane_in_state(&intel_state->base, plane,
+				       old_plane_state, new_plane_state, i) {
+		if (new_plane_state->fence) {
+			ret = dma_fence_wait_timeout(new_plane_state->fence,
+						     false,
+						     i915_fence_timeout(i915));
+			if (ret <= 0)
+				break;
 
-		if (i915_sw_fence_done(&intel_state->commit_ready) ||
-		    test_bit(I915_RESET_MODESET, &to_gt(dev_priv)->reset.flags))
-			break;
+			dma_fence_put(new_plane_state->fence);
+			new_plane_state->fence = NULL;
+		}
+		if (old_plane_state->fence) {
+			ret = dma_fence_wait_timeout(old_plane_state->fence,
+						     false,
+						     i915_fence_timeout(i915));
+			if (ret <= 0)
+				break;
 
-		schedule();
+			dma_fence_put(old_plane_state->fence);
+			old_plane_state->fence = NULL;
+		}
 	}
-	finish_wait(&intel_state->commit_ready.wait, &wait_fence);
-	finish_wait(bit_waitqueue(&to_gt(dev_priv)->reset.flags,
-				  I915_RESET_MODESET),
-		    &wait_reset);
 }
 
 static void intel_atomic_cleanup_work(struct work_struct *work)
@@ -7370,32 +7376,6 @@ static void intel_atomic_commit_work(struct work_struct *work)
 	intel_atomic_commit_tail(state);
 }
 
-static int
-intel_atomic_commit_ready(struct i915_sw_fence *fence,
-			  enum i915_sw_fence_notify notify)
-{
-	struct intel_atomic_state *state =
-		container_of(fence, struct intel_atomic_state, commit_ready);
-
-	switch (notify) {
-	case FENCE_COMPLETE:
-		/* we do blocking waits in the worker, nothing to do here */
-		break;
-	case FENCE_FREE:
-		{
-			struct drm_i915_private *i915 = to_i915(state->base.dev);
-			struct intel_atomic_helper *helper =
-				&i915->display.atomic_helper;
-
-			if (llist_add(&state->freed, &helper->free_list))
-				queue_work(i915->unordered_wq, &helper->free_work);
-			break;
-		}
-	}
-
-	return NOTIFY_DONE;
-}
-
 static void intel_atomic_track_fbs(struct intel_atomic_state *state)
 {
 	struct intel_plane_state *old_plane_state, *new_plane_state;
@@ -7418,10 +7398,6 @@ int intel_atomic_commit(struct drm_device *dev, struct drm_atomic_state *_state,
 
 	state->wakeref = intel_runtime_pm_get(&dev_priv->runtime_pm);
 
-	drm_atomic_state_get(&state->base);
-	i915_sw_fence_init(&state->commit_ready,
-			   intel_atomic_commit_ready);
-
 	/*
 	 * The intel_legacy_cursor_update() fast path takes care
 	 * of avoiding the vblank waits for simple cursor
@@ -7454,7 +7430,6 @@ int intel_atomic_commit(struct drm_device *dev, struct drm_atomic_state *_state,
 	if (ret) {
 		drm_dbg_atomic(&dev_priv->drm,
 			       "Preparing state failed with %i\n", ret);
-		i915_sw_fence_commit(&state->commit_ready);
 		intel_runtime_pm_put(&dev_priv->runtime_pm, state->wakeref);
 		return ret;
 	}
@@ -7470,8 +7445,6 @@ int intel_atomic_commit(struct drm_device *dev, struct drm_atomic_state *_state,
 		struct intel_crtc *crtc;
 		int i;
 
-		i915_sw_fence_commit(&state->commit_ready);
-
 		for_each_new_intel_crtc_in_state(state, crtc, new_crtc_state, i)
 			intel_color_cleanup_commit(new_crtc_state);
 
@@ -7485,7 +7458,6 @@ int intel_atomic_commit(struct drm_device *dev, struct drm_atomic_state *_state,
 	drm_atomic_state_get(&state->base);
 	INIT_WORK(&state->base.commit_work, intel_atomic_commit_work);
 
-	i915_sw_fence_commit(&state->commit_ready);
 	if (nonblock && state->modeset) {
 		queue_work(dev_priv->display.wq.modeset, &state->base.commit_work);
 	} else if (nonblock) {
diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
index 8d8b2f8d37a9..a685c527c7d1 100644
--- a/drivers/gpu/drm/i915/display/intel_display_types.h
+++ b/drivers/gpu/drm/i915/display/intel_display_types.h
@@ -670,8 +670,6 @@ struct intel_atomic_state {
 
 	bool rps_interactive;
 
-	struct i915_sw_fence commit_ready;
-
 	struct llist_node freed;
 };
 
-- 
2.34.1



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