[Freedreno] [PATCH 11/12] drm/msm/dpu: gracefully handle null fb commits for writeback

[Abhinav Kumar]

kms_writeback test cases also verify with a null fb for the
writeback connector job. In addition there are also other
commit paths which can result in kickoffs without a valid
framebuffer like while closing the fb which results in the
callback to drm_atomic_helper_dirtyfb() which internally
triggers a commit.

Add protection in the dpu driver to ensure that commits for
writeback encoders without a valid fb are gracefully skipped.

Signed-off-by: Abhinav Kumar <quic_abhinavk at quicinc.com>
---
 drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c            |  9 +++++++++
 drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c         | 21 +++++++++++++++++++++
 drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h         |  6 ++++++
 drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys.h    |  1 +
 drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_wb.c | 12 ++++++++++++
 5 files changed, 49 insertions(+)

diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
index e7c9fe1..f7963b0 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
@@ -869,6 +869,13 @@ void dpu_crtc_commit_kickoff(struct drm_crtc *crtc)
 
 	DPU_ATRACE_BEGIN("crtc_commit");
 
+	drm_for_each_encoder_mask(encoder, crtc->dev,
+			crtc->state->encoder_mask) {
+		if (!dpu_encoder_has_valid_fb(encoder)) {
+			DRM_DEBUG_ATOMIC("invalid FB not kicking off crtc\n");
+			goto end;
+		}
+	}
 	/*
 	 * Encoder will flush/start now, unless it has a tx pending. If so, it
 	 * may delay and flush at an irq event (e.g. ppdone)
@@ -891,6 +898,8 @@ void dpu_crtc_commit_kickoff(struct drm_crtc *crtc)
 		dpu_encoder_kickoff(encoder);
 
 	reinit_completion(&dpu_crtc->frame_done_comp);
+
+end:
 	DPU_ATRACE_END("crtc_commit");
 }
 
diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
index 3746432..e990dbc 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
@@ -1832,6 +1832,27 @@ void dpu_encoder_prepare_for_kickoff(struct drm_encoder *drm_enc)
 	}
 }
 
+bool dpu_encoder_has_valid_fb(struct drm_encoder *drm_enc)
+{
+	struct dpu_encoder_virt *dpu_enc;
+	unsigned int i;
+	struct dpu_encoder_phys *phys;
+
+	dpu_enc = to_dpu_encoder_virt(drm_enc);
+
+	if (drm_enc->encoder_type == DRM_MODE_ENCODER_VIRTUAL) {
+		for (i = 0; i < dpu_enc->num_phys_encs; i++) {
+			phys = dpu_enc->phys_encs[i];
+			if (phys->ops.has_valid_output_fb && !phys->ops.has_valid_output_fb(phys)) {
+				DPU_DEBUG("invalid FB not kicking off\n");
+				return false;
+			}
+		}
+	}
+
+	return true;
+}
+
 void dpu_encoder_kickoff(struct drm_encoder *drm_enc)
 {
 	struct dpu_encoder_virt *dpu_enc;
diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h
index da5b6d6..63d90b8 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h
@@ -187,4 +187,10 @@ void dpu_encoder_prepare_wb_job(struct drm_encoder *drm_enc,
 void dpu_encoder_cleanup_wb_job(struct drm_encoder *drm_enc,
 		struct drm_writeback_job *job);
 
+/**
+ * dpu_encoder_has_valid_fb - cleanup writeback job for the encoder.
+ * @drm_enc:    Pointer to drm encoder structure
+ */
+bool dpu_encoder_has_valid_fb(struct drm_encoder *drm_enc);
+
 #endif /* __DPU_ENCODER_H__ */
diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys.h b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys.h
index 80da0a9..5b45b3c 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys.h
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys.h
@@ -151,6 +151,7 @@ struct dpu_encoder_phys_ops {
 			struct drm_writeback_job *job);
 	void (*cleanup_wb_job)(struct dpu_encoder_phys *phys_enc,
 			struct drm_writeback_job *job);
+	bool (*has_valid_output_fb)(struct dpu_encoder_phys *phys_enc);
 };
 
 /**
diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_wb.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_wb.c
index 783f83e..7eeed79 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_wb.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_wb.c
@@ -717,6 +717,16 @@ static void dpu_encoder_phys_wb_cleanup_wb_job(struct dpu_encoder_phys *phys_enc
 	wb_enc->wb_conn = NULL;
 }
 
+static bool dpu_encoder_phys_wb_has_valid_fb(struct dpu_encoder_phys *phys_enc)
+{
+	struct dpu_encoder_phys_wb *wb_enc = to_dpu_encoder_phys_wb(phys_enc);
+
+	if (wb_enc->wb_job)
+		return true;
+	else
+		return false;
+}
+
 /**
  * dpu_encoder_phys_wb_init_ops - initialize writeback operations
  * @ops:	Pointer to encoder operation table
@@ -738,6 +748,8 @@ static void dpu_encoder_phys_wb_init_ops(struct dpu_encoder_phys_ops *ops)
 	ops->prepare_wb_job = dpu_encoder_phys_wb_prepare_wb_job;
 	ops->cleanup_wb_job = dpu_encoder_phys_wb_cleanup_wb_job;
 	ops->irq_control = dpu_encoder_phys_wb_irq_ctrl;
+	ops->has_valid_output_fb = dpu_encoder_phys_wb_has_valid_fb;
+
 }
 
 /**
-- 
2.7.4