linux-kernel - [PATCH 09/19] drm/msm/dp: Replace ST_DISPLAY_OFF with power_on in atomic

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Message-Id: <20250711-hpd-refactor-v1-9-33cbac823f34@oss.qualcomm.com>
Date: Fri, 11 Jul 2025 17:58:14 -0700
From: Jessica Zhang <jessica.zhang@....qualcomm.com>
To: Rob Clark <robin.clark@....qualcomm.com>,
        Abhinav Kumar <abhinav.kumar@...ux.dev>,
        Dmitry Baryshkov <lumag@...nel.org>, Sean Paul <sean@...rly.run>,
        Marijn Suijten <marijn.suijten@...ainline.org>,
        David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>,
        Jessica Zhang <jessica.zhang@....qualcomm.com>
Cc: linux-arm-msm@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        freedreno@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
        Yongxing Mou <quic_yongmou@...cinc.com>,
        Abhinav Kumar <quic_abhinavk@...cinc.com>
Subject: [PATCH 09/19] drm/msm/dp: Replace ST_DISPLAY_OFF with power_on in
 atomic_enable()

From: Abhinav Kumar <quic_abhinavk@...cinc.com>

ST_DISPLAY_OFF check in msm_dp_bridge_atomic_enable() is used to check
that if the display was disabled while still hotplugged, phy needs
to be re-initialized.

This can be replaced with a different check as it just means the DP cable
is connected but without display being powered on. Replace the
ST_DISPLAY_OFF check with a combination of connected and
power_on checks.

Signed-off-by: Abhinav Kumar <quic_abhinavk@...cinc.com>
Signed-off-by: Jessica Zhang <jessica.zhang@....qualcomm.com>
---
 drivers/gpu/drm/msm/dp/dp_display.c | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
index 98f5274f123e..6535c1cccf84 100644
--- a/drivers/gpu/drm/msm/dp/dp_display.c
+++ b/drivers/gpu/drm/msm/dp/dp_display.c
@@ -1564,7 +1564,6 @@ void msm_dp_bridge_atomic_enable(struct drm_bridge *drm_bridge,
 	struct msm_dp *dp = msm_dp_bridge->msm_dp_display;
 	int rc = 0;
 	struct msm_dp_display_private *msm_dp_display;
-	u32 hpd_state;
 	bool force_link_train = false;
 
 	msm_dp_display = container_of(dp, struct msm_dp_display_private, msm_dp_display);
@@ -1585,7 +1584,6 @@ void msm_dp_bridge_atomic_enable(struct drm_bridge *drm_bridge,
 		return;
 	}
 
-	hpd_state = msm_dp_display->hpd_state;
 	if (!dp->connected) {
 		mutex_unlock(&msm_dp_display->event_mutex);
 		return;
@@ -1598,9 +1596,7 @@ void msm_dp_bridge_atomic_enable(struct drm_bridge *drm_bridge,
 		return;
 	}
 
-	hpd_state =  msm_dp_display->hpd_state;
-
-	if (hpd_state == ST_DISPLAY_OFF) {
+	if (dp->connected && !dp->power_on) {
 		msm_dp_display_host_phy_init(msm_dp_display);
 		force_link_train = true;
 	}

-- 
2.50.1