drm/msm/dpu: Don't always set merge_3d pending flush

Don't set the merge_3d pending flush bits if the mode_3d is
BLEND_3D_NONE.

Always flushing merge_3d can cause timeout issues when there are
multiple commits with concurrent writeback enabled.

This is because the video phys enc waits for the hw_ctl flush register
to be completely cleared [1] in its wait_for_commit_done(), but the WB
encoder always sets the merge_3d pending flush during each commit
regardless of if the merge_3d is actually active.

This means that the hw_ctl flush register will never be 0 when there are
multiple CWB commits and the video phys enc will hit vblank timeout
errors after the first CWB commit.

[1] commit fe9df3f ("drm/msm/dpu: add real wait_for_commit_done()")

Fixes: 3e79527 ("drm/msm/dpu: enable merge_3d support on sm8150/sm8250")
Fixes: d7d0e73 ("drm/msm/dpu: introduce the dpu_encoder_phys_* for writeback")
Signed-off-by: Jessica Zhang <quic_jesszhan@quicinc.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/619092/
Link: https://lore.kernel.org/r/20241009-mode3d-fix-v1-1-c0258354fadc@quicinc.com
Signed-off-by: Abhinav Kumar <quic_abhinavk@quicinc.com>

drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_vid.c

@@ -440,10 +440,12 @@ static void dpu_encoder_phys_vid_enable(struct dpu_encoder_phys *phys_enc)
 	struct dpu_hw_ctl *ctl;
 	const struct msm_format *fmt;
 	u32 fmt_fourcc;
+	u32 mode_3d;
 
 	ctl = phys_enc->hw_ctl;
 	fmt_fourcc = dpu_encoder_get_drm_fmt(phys_enc);
 	fmt = mdp_get_format(&phys_enc->dpu_kms->base, fmt_fourcc, 0);
+	mode_3d = dpu_encoder_helper_get_3d_blend_mode(phys_enc);
 
 	DPU_DEBUG_VIDENC(phys_enc, "\n");
 
@@ -466,7 +468,8 @@ static void dpu_encoder_phys_vid_enable(struct dpu_encoder_phys *phys_enc)
 		goto skip_flush;
 
 	ctl->ops.update_pending_flush_intf(ctl, phys_enc->hw_intf->idx);
-	if (ctl->ops.update_pending_flush_merge_3d && phys_enc->hw_pp->merge_3d)
+	if (mode_3d && ctl->ops.update_pending_flush_merge_3d &&
+	    phys_enc->hw_pp->merge_3d)
 		ctl->ops.update_pending_flush_merge_3d(ctl, phys_enc->hw_pp->merge_3d->idx);
 
 	if (ctl->ops.update_pending_flush_cdm && phys_enc->hw_cdm)

drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_wb.c

@@ -275,6 +275,7 @@ static void _dpu_encoder_phys_wb_update_flush(struct dpu_encoder_phys *phys_enc)
 	struct dpu_hw_pingpong *hw_pp;
 	struct dpu_hw_cdm *hw_cdm;
 	u32 pending_flush = 0;
+	u32 mode_3d;
 
 	if (!phys_enc)
 		return;
@@ -283,6 +284,7 @@ static void _dpu_encoder_phys_wb_update_flush(struct dpu_encoder_phys *phys_enc)
 	hw_pp = phys_enc->hw_pp;
 	hw_ctl = phys_enc->hw_ctl;
 	hw_cdm = phys_enc->hw_cdm;
+	mode_3d = dpu_encoder_helper_get_3d_blend_mode(phys_enc);
 
 	DPU_DEBUG("[wb:%d]\n", hw_wb->idx - WB_0);
 
@@ -294,7 +296,8 @@ static void _dpu_encoder_phys_wb_update_flush(struct dpu_encoder_phys *phys_enc)
 	if (hw_ctl->ops.update_pending_flush_wb)
 		hw_ctl->ops.update_pending_flush_wb(hw_ctl, hw_wb->idx);
 
-	if (hw_ctl->ops.update_pending_flush_merge_3d && hw_pp && hw_pp->merge_3d)
+	if (mode_3d && hw_ctl->ops.update_pending_flush_merge_3d &&
+	    hw_pp && hw_pp->merge_3d)
 		hw_ctl->ops.update_pending_flush_merge_3d(hw_ctl,
 				hw_pp->merge_3d->idx);