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From: Jessica Zhang <jessica.zhang@oss.qualcomm.com>
To: Rob Clark <robin.clark@oss.qualcomm.com>,
	Abhinav Kumar <abhinav.kumar@linux.dev>,
	Dmitry Baryshkov <lumag@kernel.org>, Sean Paul <sean@poorly.run>,
	Marijn Suijten <marijn.suijten@somainline.org>,
	David Airlie <airlied@gmail.com>, Simona Vetter <simona@ffwll.ch>,
	Jessica Zhang <jessica.zhang@oss.qualcomm.com>,
	Kuogee Hsieh <quic_khsieh@quicinc.com>
Cc: linux-arm-msm@vger.kernel.org, dri-devel@lists.freedesktop.org,
	freedreno@lists.freedesktop.org, linux-kernel@vger.kernel.org,
	Yongxing Mou <quic_yongmou@quicinc.com>
Subject: [PATCH v2 10/12] drm/msm/dp: Return early from atomic_enable() if cable is not connected
Date: Fri, 08 Aug 2025 17:35:22 -0700	[thread overview]
Message-ID: <20250808-hpd-refactor-v2-10-7f4e1e741aa3@oss.qualcomm.com> (raw)
In-Reply-To: <20250808-hpd-refactor-v2-0-7f4e1e741aa3@oss.qualcomm.com>

Replace the ST_MAINLINK_READY check here with a check for sink count.

Since atomic_check() fails if the link isn't ready, we technically don't
need a check against ST_MAINLINK_READY. The hpd_state should also never
really hit ST_DISPLAY_OFF since atomic_enable() shouldn't be called
twice in a row without an atomic_disable() in between.

That being said, it is possible for the cable to be disconnected after
atomic_check() but before atomic_enable(). So let's change this check to
guard against sink_count instead.

Signed-off-by: Jessica Zhang <jessica.zhang@oss.qualcomm.com>
---
 drivers/gpu/drm/msm/dp/dp_display.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
index dd3fdeaacc91..82f0b6bdbf39 100644
--- a/drivers/gpu/drm/msm/dp/dp_display.c
+++ b/drivers/gpu/drm/msm/dp/dp_display.c
@@ -1444,7 +1444,7 @@ void msm_dp_bridge_atomic_enable(struct drm_bridge *drm_bridge,
 	}
 
 	hpd_state = msm_dp_display->hpd_state;
-	if (hpd_state != ST_DISPLAY_OFF && hpd_state != ST_MAINLINK_READY)
+	if (msm_dp_display->link->sink_count == 0)
 		return;
 
 	rc = msm_dp_display_set_mode(dp, &msm_dp_display->msm_dp_mode);

-- 
2.50.1


  parent reply	other threads:[~2025-08-09  0:35 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-08-09  0:35 [PATCH v2 00/12] drm/msm/dp: Drop the HPD state machine Jessica Zhang
2025-08-09  0:35 ` [PATCH v2 01/12] drm/msm/dp: fix HPD state status bit shift value Jessica Zhang
2025-08-09  0:38   ` Dmitry Baryshkov
2025-08-09  0:35 ` [PATCH v2 02/12] drm/msm/dp: Fix the ISR_* enum values Jessica Zhang
2025-08-09  0:35 ` [PATCH v2 03/12] drm/msm/dp: Read DPCD and sink count in bridge detect() Jessica Zhang
2025-08-09  0:44   ` Dmitry Baryshkov
2025-08-09  0:35 ` [PATCH v2 04/12] drm/msm/dp: Move link training to atomic_enable() Jessica Zhang
2025-08-09  0:45   ` Dmitry Baryshkov
2025-08-09  0:53     ` Jessica Zhang
2025-08-09  0:51   ` Dmitry Baryshkov
2025-08-09  0:35 ` [PATCH v2 05/12] drm/msm/dp: Drop EV_USER_NOTIFICATION Jessica Zhang
2025-08-09  2:14   ` Dmitry Baryshkov
2025-08-09  0:35 ` [PATCH v2 06/12] drm/msm/dp: Use drm_bridge_hpd_notify() Jessica Zhang
2025-08-09  6:46   ` Dmitry Baryshkov
2025-08-09  0:35 ` [PATCH v2 07/12] drm/msm/dp: Handle internal HPD IRQ in hpd_notify() Jessica Zhang
2025-08-09  7:05   ` Dmitry Baryshkov
2025-08-09  0:35 ` [PATCH v2 08/12] drm/msm/dp: Drop event waitqueue Jessica Zhang
2025-08-09  7:08   ` Dmitry Baryshkov
2025-08-09  0:35 ` [PATCH v2 09/12] drm/msm/dp: remove redundant checks related to ST_DISPLAY_OFF in plug handler Jessica Zhang
2025-08-09  7:10   ` Dmitry Baryshkov
2025-08-09  0:35 ` Jessica Zhang [this message]
2025-08-09  0:35 ` [PATCH v2 11/12] drm/msm/dp: drop the entire HPD state machine Jessica Zhang
2025-08-09  7:26   ` Dmitry Baryshkov
2025-08-09  0:35 ` [PATCH v2 12/12] drm/msm/dp: Add sink_count and link_ready to debug logs Jessica Zhang

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