linux-kernel - [PATCH v7 13/15] drm/msm/disp/dpu: wait for extra vsync till timing engine status is disabled

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Date:   Tue, 13 Sep 2022 20:21:14 +0530
From:   Vinod Polimera <quic_vpolimer@...cinc.com>
To:     dri-devel@...ts.freedesktop.org, linux-arm-msm@...r.kernel.org,
        freedreno@...ts.freedesktop.org, devicetree@...r.kernel.org
Cc:     Vinod Polimera <quic_vpolimer@...cinc.com>,
        linux-kernel@...r.kernel.org, robdclark@...il.com,
        dianders@...omium.org, swboyd@...omium.org,
        quic_kalyant@...cinc.com, dmitry.baryshkov@...aro.org,
        quic_khsieh@...cinc.com, quic_vproddut@...cinc.com,
        quic_bjorande@...cinc.com, quic_aravindh@...cinc.com,
        quic_abhinavk@...cinc.com, quic_sbillaka@...cinc.com
Subject: [PATCH v7 13/15] drm/msm/disp/dpu: wait for extra vsync till timing engine status is disabled

There can be a race between timing gen disable and vblank irq. The
wait post timing gen disable may return early but intf disable sequence
might not be completed. Ensure that, intf status is disabled before
we retire the function.

Signed-off-by: Vinod Polimera <quic_vpolimer@...cinc.com>
---
 .../gpu/drm/msm/disp/dpu1/dpu_encoder_phys_vid.c    | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_vid.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_vid.c
index 2c14646..5a0dc54 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_vid.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_vid.c
@@ -525,6 +525,7 @@ static void dpu_encoder_phys_vid_disable(struct dpu_encoder_phys *phys_enc)
 {
 	unsigned long lock_flags;
 	int ret;
+	struct intf_status intf_status = {0};
 
 	if (!phys_enc->parent || !phys_enc->parent->dev) {
 		DPU_ERROR("invalid encoder/device\n");
@@ -569,6 +570,26 @@ static void dpu_encoder_phys_vid_disable(struct dpu_encoder_phys *phys_enc)
 		}
 	}
 
+	if (phys_enc->hw_intf && phys_enc->hw_intf->ops.get_status)
+		phys_enc->hw_intf->ops.get_status(phys_enc->hw_intf, &intf_status);
+
+	/*
+	 * Wait for a vsync if timing en status is on after timing engine
+	 * is disabled.
+	 */
+	if (intf_status.is_en && dpu_encoder_phys_vid_is_master(phys_enc)) {
+		spin_lock_irqsave(phys_enc->enc_spinlock, lock_flags);
+		dpu_encoder_phys_inc_pending(phys_enc);
+		spin_unlock_irqrestore(phys_enc->enc_spinlock, lock_flags);
+		ret = dpu_encoder_phys_vid_wait_for_vblank(phys_enc);
+		if (ret) {
+			atomic_set(&phys_enc->pending_kickoff_cnt, 0);
+			DRM_ERROR("wait disable failed: id:%u intf:%d ret:%d\n",
+				  DRMID(phys_enc->parent),
+				  phys_enc->hw_intf->idx - INTF_0, ret);
+		}
+	}
+
 	phys_enc->enable_state = DPU_ENC_DISABLED;
 }
 
-- 
2.7.4