linux-kernel - [PATCH 4/4] drm/msm/dp: remove ST_DISPLAY_OFF as a hpd

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Message-Id: <20250529-hpd_display_off-v1-4-ce33bac2987c@oss.qualcomm.com>
Date: Thu, 29 May 2025 16:13:46 -0700
From: Jessica Zhang <jessica.zhang@....qualcomm.com>
To: Rob Clark <robdclark@...il.com>, Sean Paul <sean@...rly.run>,
        Marijn Suijten <marijn.suijten@...ainline.org>,
        David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>,
        Abhinav Kumar <quic_abhinavk@...cinc.com>,
        Dmitry Baryshkov <lumag@...nel.org>
Cc: linux-arm-msm@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        freedreno@...ts.freedesktop.org, Stephen Boyd <swboyd@...omium.org>,
        Doug Anderson <dianders@...omium.org>, Johan Hovold <johan@...nel.org>,
        Bjorn Andersson <quic_bjorande@...cinc.com>,
        Abhinav Kumar <abhinav.kumar@....qualcomm.com>,
        linux-kernel@...r.kernel.org, Yongxing Mou <quic_yongmou@...cinc.com>,
        Jessica Zhang <jessica.zhang@....qualcomm.com>,
        Dmitry Baryshkov <lumag@...nel.org>
Subject: [PATCH 4/4] drm/msm/dp: remove ST_DISPLAY_OFF as a hpd_state

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 hpd_state was still ST_CONNECTED but without display
being powered on. Replace the ST_DISPLAY_OFF check with a combination
of connected and power_on checks.

Since all consumers of ST_DISPLAY_OFF have now been removed,
drop ST_DISPLAY_OFF from the list of hpd_states as technically
this was never a 'hpd' state anyway.

Signed-off-by: Abhinav Kumar <quic_abhinavk@...cinc.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
Signed-off-by: Jessica Zhang <jessica.zhang@....qualcomm.com>
---
 drivers/gpu/drm/msm/dp/dp_display.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
index 785c813d2b31..6f05a939ce9e 100644
--- a/drivers/gpu/drm/msm/dp/dp_display.c
+++ b/drivers/gpu/drm/msm/dp/dp_display.c
@@ -50,7 +50,6 @@ enum {
 	ST_MAINLINK_READY,
 	ST_CONNECTED,
 	ST_DISCONNECT_PENDING,
-	ST_DISPLAY_OFF,
 };
 
 enum {
@@ -1526,7 +1525,7 @@ void msm_dp_bridge_atomic_enable(struct drm_bridge *drm_bridge,
 
 	hpd_state =  msm_dp_display->hpd_state;
 
-	if (hpd_state == ST_DISPLAY_OFF) {
+	if (hpd_state == ST_CONNECTED && !dp->power_on) {
 		msm_dp_display_host_phy_init(msm_dp_display);
 		force_link_train = true;
 	}
@@ -1584,8 +1583,6 @@ void msm_dp_bridge_atomic_post_disable(struct drm_bridge *drm_bridge,
 	if (hpd_state == ST_DISCONNECT_PENDING) {
 		/* completed disconnection */
 		msm_dp_display->hpd_state = ST_DISCONNECTED;
-	} else {
-		msm_dp_display->hpd_state = ST_DISPLAY_OFF;
 	}
 
 	drm_dbg_dp(dp->drm_dev, "type=%d Done\n", dp->connector_type);

-- 
2.49.0