[PATCH 21/28] drm/i915/writeback: Define writeback frame capture function

Suraj Kandpal suraj.kandpal at intel.com
Fri Jul 25 05:04:02 UTC 2025


Define the commit function to be called at atomic_commit_tail
if drm_writeback_job is available. This function calls the
capture function and queues the job to be called later via
interrupt handler when the job is complete.

Signed-off-by: Suraj Kandpal <suraj.kandpal at intel.com>
---
 drivers/gpu/drm/i915/display/intel_display.c  |  3 ++
 .../gpu/drm/i915/display/intel_writeback.c    | 54 +++++++++++++++++++
 .../gpu/drm/i915/display/intel_writeback.h    |  4 ++
 3 files changed, 61 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
index c2d1156de8e9..67ed3d6791b8 100644
--- a/drivers/gpu/drm/i915/display/intel_display.c
+++ b/drivers/gpu/drm/i915/display/intel_display.c
@@ -125,6 +125,7 @@
 #include "intel_vga.h"
 #include "intel_vrr.h"
 #include "intel_wm.h"
+#include "intel_writeback.h"
 #include "skl_scaler.h"
 #include "skl_universal_plane.h"
 #include "skl_watermark.h"
@@ -7429,6 +7430,8 @@ static void intel_atomic_commit_tail(struct intel_atomic_state *state)
 	/* FIXME probably need to sequence this properly */
 	intel_program_dpkgc_latency(state);
 
+	intel_writeback_atomic_commit(state);
+
 	intel_wait_for_vblank_workers(state);
 
 	/* FIXME: We should call drm_atomic_helper_commit_hw_done() here
diff --git a/drivers/gpu/drm/i915/display/intel_writeback.c b/drivers/gpu/drm/i915/display/intel_writeback.c
index 2db9ae7d810f..25e293cc5be4 100644
--- a/drivers/gpu/drm/i915/display/intel_writeback.c
+++ b/drivers/gpu/drm/i915/display/intel_writeback.c
@@ -244,6 +244,60 @@ static int intel_writeback_atomic_check(struct drm_connector *connector,
 	return 0;
 }
 
+static void intel_writeback_capture(struct intel_atomic_state *state,
+				    struct intel_connector *connector)
+{
+	struct intel_display *display = to_intel_display(connector);
+	struct intel_writeback_connector *wb_conn =
+		conn_to_intel_writeback_connector(connector);
+	enum transcoder trans = wb_conn->trans;
+	u32 val = 0;
+
+	val |= START_TRIGGER_FRAME | WD_FRAME_NUMBER(wb_conn->frame_num);
+	intel_de_rmw(display, WD_TRANS_FUNC_CTL(trans),
+		     START_TRIGGER_FRAME | WD_FRAME_NUMBER_MASK,
+		     val);
+
+	if (intel_de_wait_for_set(display, WD_FRAME_STATUS(trans), WD_FRAME_COMPLETE,
+				  50)) {
+		drm_dbg_kms(display->drm,
+			    "Frame was not captured after triggering a capture\n");
+		intel_de_rmw(display, WD_TRANS_FUNC_CTL(trans),
+			     STOP_TRIGGER_FRAME,
+			     STOP_TRIGGER_FRAME);
+	} else {
+		drm_writeback_signal_completion(&wb_conn->base, 0);
+		intel_de_write(display, WD_FRAME_STATUS(trans), WD_FRAME_COMPLETE);
+		wb_conn->frame_num++;
+		if (wb_conn->frame_num > 7)
+			wb_conn->frame_num = 1;
+		wb_conn->job = NULL;
+	}
+}
+
+void intel_writeback_atomic_commit(struct intel_atomic_state *state)
+{
+	struct drm_connector *connector;
+	struct drm_connector_state *conn_state;
+	int i;
+
+	for_each_new_connector_in_state(&state->base, connector, conn_state, i) {
+		struct intel_writeback_job *job;
+		struct intel_connector *intel_connector = to_intel_connector(connector);
+
+		if (!conn_state)
+			return;
+
+		if (conn_state->writeback_job && conn_state->writeback_job->fb) {
+			WARN_ON(connector->connector_type != DRM_MODE_CONNECTOR_WRITEBACK);
+			job = conn_state->writeback_job->priv;
+
+			drm_writeback_queue_job(job->wb_connector, conn_state);
+			intel_writeback_capture(state, intel_connector);
+		}
+	}
+}
+
 static void intel_writeback_enable_encoder(struct intel_atomic_state *state,
 					   struct intel_encoder *encoder,
 					   const struct intel_crtc_state *crtc_state,
diff --git a/drivers/gpu/drm/i915/display/intel_writeback.h b/drivers/gpu/drm/i915/display/intel_writeback.h
index 5911684cb81a..3c145cf73e20 100644
--- a/drivers/gpu/drm/i915/display/intel_writeback.h
+++ b/drivers/gpu/drm/i915/display/intel_writeback.h
@@ -8,10 +8,14 @@
 
 #include <linux/types.h>
 
+#include "intel_display_types.h"
+
+struct intel_atomic_state;
 struct intel_display;
 struct intel_writeback_connector;
 
 int intel_writeback_init(struct intel_display *display);
+void intel_writeback_atomic_commit(struct intel_atomic_state *state);
 
 #endif /* __INTEL_WRITEBACK_H__ */
 
-- 
2.34.1



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