[PATCH 0/7] drm/panel: make prepare / enable / disable / unprepare return void

[PATCH 0/7] drm/panel: make prepare / enable / disable / unprepare return void

[Dmitry Baryshkov]

While it makes sense for panel callbacks to be able to return an error,
the state-management functions from drm_panel API are usually called
from atomic callbacks, which can not fails and must return void. Make
drm_panel_prepare(), drm_panel_enable(), drm_panel_disable() and
drm_panel_unprepare() follow the same calling convention and return
void.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
---
Dmitry Baryshkov (7):
      drm/bridge: analogix_dp: drop extra calls to analogix_dp_prepare_panel()
      drm/bridge: analogix_dp: drop unused argument to analogix_dp_prepare_panel()
      drm/bridge: analogic_dp: drop panel_is_modeset
      drm/bridge: analogic_dp: drop panel_lock
      drm/bridge: analogix_dp: inline analogix_dp_prepare_panel()
      drm/bridge: analogix_dp: ignore return values of drm_panel_* calls
      drm/panel: make prepare/enable and disable/unprepare calls return void

 drivers/gpu/drm/bridge/analogix/analogix_dp_core.c | 107 ++-------------------
 drivers/gpu/drm/bridge/analogix/analogix_dp_core.h |   3 -
 drivers/gpu/drm/drm_panel.c                        |  54 ++++-------
 drivers/gpu/drm/panel/panel-newvision-nv3051d.c    |   9 +-
 include/drm/drm_panel.h                            |   8 +-
 5 files changed, 33 insertions(+), 148 deletions(-)
---
base-commit: bfb20a655848a9088e3e9ae24b1dcce1bbf016c2
change-id: 20250401-panel-return-void-d461c71ebd35

Best regards,
-- 
Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>

[PATCH 1/7] drm/bridge: analogix_dp: drop extra calls to analogix_dp_prepare_panel()

[Dmitry Baryshkov]

The analogix_dp_prepare_panel() returns immediately if there is no
attached panel. Drop several calls to this function which are performed
when dp->plat_data->panel is NULL.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
---
 drivers/gpu/drm/bridge/analogix/analogix_dp_core.c | 22 +---------------------
 1 file changed, 1 insertion(+), 21 deletions(-)

diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
index 042154e2d8ccd74ac2dc27fe527e810a50e08a09..ab1cfc340aa95bbf13fe021bd33227b565a5458d 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
@@ -1005,17 +1005,11 @@ static int analogix_dp_get_modes(struct drm_connector *connector)
 {
 	struct analogix_dp_device *dp = to_dp(connector);
 	const struct drm_edid *drm_edid;
-	int ret, num_modes = 0;
+	int num_modes = 0;
 
 	if (dp->plat_data->panel) {
 		num_modes += drm_panel_get_modes(dp->plat_data->panel, connector);
 	} else {
-		ret = analogix_dp_prepare_panel(dp, true, false);
-		if (ret) {
-			DRM_ERROR("Failed to prepare panel (%d)\n", ret);
-			return 0;
-		}
-
 		drm_edid = drm_edid_read_ddc(connector, &dp->aux.ddc);
 
 		drm_edid_connector_update(&dp->connector, drm_edid);
@@ -1024,10 +1018,6 @@ static int analogix_dp_get_modes(struct drm_connector *connector)
 			num_modes += drm_edid_connector_add_modes(&dp->connector);
 			drm_edid_free(drm_edid);
 		}
-
-		ret = analogix_dp_prepare_panel(dp, false, false);
-		if (ret)
-			DRM_ERROR("Failed to unprepare panel (%d)\n", ret);
 	}
 
 	if (dp->plat_data->get_modes)
@@ -1087,19 +1077,9 @@ analogix_dp_detect(struct drm_connector *connector, bool force)
 	if (dp->plat_data->panel)
 		return connector_status_connected;
 
-	ret = analogix_dp_prepare_panel(dp, true, false);
-	if (ret) {
-		DRM_ERROR("Failed to prepare panel (%d)\n", ret);
-		return connector_status_disconnected;
-	}
-
 	if (!analogix_dp_detect_hpd(dp))
 		status = connector_status_connected;
 
-	ret = analogix_dp_prepare_panel(dp, false, false);
-	if (ret)
-		DRM_ERROR("Failed to unprepare panel (%d)\n", ret);
-
 	return status;
 }
 

-- 
2.39.5

[PATCH 2/7] drm/bridge: analogix_dp: drop unused argument to analogix_dp_prepare_panel()

[Dmitry Baryshkov]

After previous cleanup all calling sites pass true as is_modeset_prepare
argument to analogix_dp_prepare_panel(). Drop dead code depending on
that argument being false.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
---
 drivers/gpu/drm/bridge/analogix/analogix_dp_core.c | 19 +++++--------------
 1 file changed, 5 insertions(+), 14 deletions(-)

diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
index ab1cfc340aa95bbf13fe021bd33227b565a5458d..82dc4b01806f9728dc882b0128171838e81f21b0 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
@@ -963,13 +963,13 @@ static int analogix_dp_disable_psr(struct analogix_dp_device *dp)
  * If @prepare is true, this function will prepare the panel. Conversely, if it
  * is false, the panel will be unprepared.
  *
- * If @is_modeset_prepare is true, the function will disregard the current state
+ * The function will disregard the current state
  * of the panel and either prepare/unprepare the panel based on @prepare. Once
  * it finishes, it will update dp->panel_is_modeset to reflect the current state
  * of the panel.
  */
 static int analogix_dp_prepare_panel(struct analogix_dp_device *dp,
-				     bool prepare, bool is_modeset_prepare)
+				     bool prepare)
 {
 	int ret = 0;
 
@@ -978,13 +978,6 @@ static int analogix_dp_prepare_panel(struct analogix_dp_device *dp,
 
 	mutex_lock(&dp->panel_lock);
 
-	/*
-	 * Exit early if this is a temporary prepare/unprepare and we're already
-	 * modeset (since we neither want to prepare twice or unprepare early).
-	 */
-	if (dp->panel_is_modeset && !is_modeset_prepare)
-		goto out;
-
 	if (prepare)
 		ret = drm_panel_prepare(dp->plat_data->panel);
 	else
@@ -993,8 +986,7 @@ static int analogix_dp_prepare_panel(struct analogix_dp_device *dp,
 	if (ret)
 		goto out;
 
-	if (is_modeset_prepare)
-		dp->panel_is_modeset = prepare;
+	dp->panel_is_modeset = prepare;
 
 out:
 	mutex_unlock(&dp->panel_lock);
@@ -1072,7 +1064,6 @@ analogix_dp_detect(struct drm_connector *connector, bool force)
 {
 	struct analogix_dp_device *dp = to_dp(connector);
 	enum drm_connector_status status = connector_status_disconnected;
-	int ret;
 
 	if (dp->plat_data->panel)
 		return connector_status_connected;
@@ -1194,7 +1185,7 @@ static void analogix_dp_bridge_atomic_pre_enable(struct drm_bridge *bridge,
 	if (old_crtc_state && old_crtc_state->self_refresh_active)
 		return;
 
-	ret = analogix_dp_prepare_panel(dp, true, true);
+	ret = analogix_dp_prepare_panel(dp, true);
 	if (ret)
 		DRM_ERROR("failed to setup the panel ret = %d\n", ret);
 }
@@ -1294,7 +1285,7 @@ static void analogix_dp_bridge_disable(struct drm_bridge *bridge)
 
 	pm_runtime_put_sync(dp->dev);
 
-	ret = analogix_dp_prepare_panel(dp, false, true);
+	ret = analogix_dp_prepare_panel(dp, false);
 	if (ret)
 		DRM_ERROR("failed to setup the panel ret = %d\n", ret);
 

-- 
2.39.5

[PATCH 3/7] drm/bridge: analogic_dp: drop panel_is_modeset

[Dmitry Baryshkov]

The dp->panel_is_modeset is now a write-only field. Drop it completely.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
---
 drivers/gpu/drm/bridge/analogix/analogix_dp_core.c | 11 +----------
 drivers/gpu/drm/bridge/analogix/analogix_dp_core.h |  1 -
 2 files changed, 1 insertion(+), 11 deletions(-)

diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
index 82dc4b01806f9728dc882b0128171838e81f21b0..704c6169116eb2601d2ad02dc7294455ceff5460 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
@@ -964,9 +964,7 @@ static int analogix_dp_disable_psr(struct analogix_dp_device *dp)
  * is false, the panel will be unprepared.
  *
  * The function will disregard the current state
- * of the panel and either prepare/unprepare the panel based on @prepare. Once
- * it finishes, it will update dp->panel_is_modeset to reflect the current state
- * of the panel.
+ * of the panel and either prepare/unprepare the panel based on @prepare.
  */
 static int analogix_dp_prepare_panel(struct analogix_dp_device *dp,
 				     bool prepare)
@@ -983,12 +981,6 @@ static int analogix_dp_prepare_panel(struct analogix_dp_device *dp,
 	else
 		ret = drm_panel_unprepare(dp->plat_data->panel);
 
-	if (ret)
-		goto out;
-
-	dp->panel_is_modeset = prepare;
-
-out:
 	mutex_unlock(&dp->panel_lock);
 	return ret;
 }
@@ -1532,7 +1524,6 @@ analogix_dp_probe(struct device *dev, struct analogix_dp_plat_data *plat_data)
 	dp->dpms_mode = DRM_MODE_DPMS_OFF;
 
 	mutex_init(&dp->panel_lock);
-	dp->panel_is_modeset = false;
 
 	/*
 	 * platform dp driver need containor_of the plat_data to get
diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
index 774d11574b095b093ddf2818ad5b84be6605c9bf..b679d5b71d276f458d905c936160f107225bc6c5 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
@@ -170,7 +170,6 @@ struct analogix_dp_device {
 	bool			psr_supported;
 
 	struct mutex		panel_lock;
-	bool			panel_is_modeset;
 
 	struct analogix_dp_plat_data *plat_data;
 };

-- 
2.39.5

[PATCH 4/7] drm/bridge: analogic_dp: drop panel_lock

[Dmitry Baryshkov]

The analogix_dp_prepare_panel() function is called from bridge's
atomic_pre_enable() and atomic_post_disable() callbacks, which can not
happen simultaneously. Drop the useless mutex.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
---
 drivers/gpu/drm/bridge/analogix/analogix_dp_core.c | 5 -----
 drivers/gpu/drm/bridge/analogix/analogix_dp_core.h | 2 --
 2 files changed, 7 deletions(-)

diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
index 704c6169116eb2601d2ad02dc7294455ceff5460..1ec4d277fe6bb03ad9eb8451ae2af5ad5ada0978 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
@@ -974,14 +974,11 @@ static int analogix_dp_prepare_panel(struct analogix_dp_device *dp,
 	if (!dp->plat_data->panel)
 		return 0;
 
-	mutex_lock(&dp->panel_lock);
-
 	if (prepare)
 		ret = drm_panel_prepare(dp->plat_data->panel);
 	else
 		ret = drm_panel_unprepare(dp->plat_data->panel);
 
-	mutex_unlock(&dp->panel_lock);
 	return ret;
 }
 
@@ -1523,8 +1520,6 @@ analogix_dp_probe(struct device *dev, struct analogix_dp_plat_data *plat_data)
 	dp->dev = &pdev->dev;
 	dp->dpms_mode = DRM_MODE_DPMS_OFF;
 
-	mutex_init(&dp->panel_lock);
-
 	/*
 	 * platform dp driver need containor_of the plat_data to get
 	 * the driver private data, so we need to store the point of
diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
index b679d5b71d276f458d905c936160f107225bc6c5..2b54120ba4a3ef55af518a0629a5c8469f275a0f 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
@@ -169,8 +169,6 @@ struct analogix_dp_device {
 	bool			fast_train_enable;
 	bool			psr_supported;
 
-	struct mutex		panel_lock;
-
 	struct analogix_dp_plat_data *plat_data;
 };
 

-- 
2.39.5

[PATCH 5/7] drm/bridge: analogix_dp: inline analogix_dp_prepare_panel()

[Dmitry Baryshkov]

The analogix_dp_prepare_panel() is now only calling a corresponding
drm_panel function. Inline it to simplify the code.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
---
 drivers/gpu/drm/bridge/analogix/analogix_dp_core.c | 43 +++++-----------------
 1 file changed, 10 insertions(+), 33 deletions(-)

diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
index 1ec4d277fe6bb03ad9eb8451ae2af5ad5ada0978..f60068011008482f7b7b2edfcab5fb1b3e9e130f 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
@@ -955,33 +955,6 @@ static int analogix_dp_disable_psr(struct analogix_dp_device *dp)
 	return analogix_dp_send_psr_spd(dp, &psr_vsc, true);
 }
 
-/*
- * This function is a bit of a catch-all for panel preparation, hopefully
- * simplifying the logic of functions that need to prepare/unprepare the panel
- * below.
- *
- * If @prepare is true, this function will prepare the panel. Conversely, if it
- * is false, the panel will be unprepared.
- *
- * The function will disregard the current state
- * of the panel and either prepare/unprepare the panel based on @prepare.
- */
-static int analogix_dp_prepare_panel(struct analogix_dp_device *dp,
-				     bool prepare)
-{
-	int ret = 0;
-
-	if (!dp->plat_data->panel)
-		return 0;
-
-	if (prepare)
-		ret = drm_panel_prepare(dp->plat_data->panel);
-	else
-		ret = drm_panel_unprepare(dp->plat_data->panel);
-
-	return ret;
-}
-
 static int analogix_dp_get_modes(struct drm_connector *connector)
 {
 	struct analogix_dp_device *dp = to_dp(connector);
@@ -1174,9 +1147,11 @@ static void analogix_dp_bridge_atomic_pre_enable(struct drm_bridge *bridge,
 	if (old_crtc_state && old_crtc_state->self_refresh_active)
 		return;
 
-	ret = analogix_dp_prepare_panel(dp, true);
-	if (ret)
-		DRM_ERROR("failed to setup the panel ret = %d\n", ret);
+	if (dp->plat_data->panel) {
+		ret = drm_panel_prepare(dp->plat_data->panel);
+		if (ret)
+			DRM_ERROR("failed to prepare the panel ret = %d\n", ret);
+	}
 }
 
 static int analogix_dp_set_bridge(struct analogix_dp_device *dp)
@@ -1274,9 +1249,11 @@ static void analogix_dp_bridge_disable(struct drm_bridge *bridge)
 
 	pm_runtime_put_sync(dp->dev);
 
-	ret = analogix_dp_prepare_panel(dp, false);
-	if (ret)
-		DRM_ERROR("failed to setup the panel ret = %d\n", ret);
+	if (dp->plat_data->panel) {
+		ret = drm_panel_unprepare(dp->plat_data->panel);
+		if (ret)
+			DRM_ERROR("failed to unprepare the panel ret = %d\n", ret);
+	}
 
 	dp->fast_train_enable = false;
 	dp->psr_supported = false;

-- 
2.39.5

[PATCH 6/7] drm/bridge: analogix_dp: ignore return values of drm_panel_* calls

[Dmitry Baryshkov]

Follow the example of other drivers and ignore return values of the
drm_panel_prepare() / unprepare() / enable() / disable() calls. There is
no possible error recovery, so the driver just logs a message.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
---
 drivers/gpu/drm/bridge/analogix/analogix_dp_core.c | 39 ++++------------------
 1 file changed, 6 insertions(+), 33 deletions(-)

diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
index f60068011008482f7b7b2edfcab5fb1b3e9e130f..c7dffdae31877ae194fc6b0a5bf21be203f7dcc4 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
@@ -838,10 +838,7 @@ static int analogix_dp_commit(struct analogix_dp_device *dp)
 	int ret;
 
 	/* Keep the panel disabled while we configure video */
-	if (dp->plat_data->panel) {
-		if (drm_panel_disable(dp->plat_data->panel))
-			DRM_ERROR("failed to disable the panel\n");
-	}
+	drm_panel_disable(dp->plat_data->panel);
 
 	ret = analogix_dp_train_link(dp);
 	if (ret) {
@@ -863,13 +860,7 @@ static int analogix_dp_commit(struct analogix_dp_device *dp)
 	}
 
 	/* Safe to enable the panel now */
-	if (dp->plat_data->panel) {
-		ret = drm_panel_enable(dp->plat_data->panel);
-		if (ret) {
-			DRM_ERROR("failed to enable the panel\n");
-			return ret;
-		}
-	}
+	drm_panel_enable(dp->plat_data->panel);
 
 	/* Check whether panel supports fast training */
 	ret = analogix_dp_fast_link_train_detection(dp);
@@ -1136,7 +1127,6 @@ static void analogix_dp_bridge_atomic_pre_enable(struct drm_bridge *bridge,
 	struct analogix_dp_device *dp = bridge->driver_private;
 	struct drm_crtc *crtc;
 	struct drm_crtc_state *old_crtc_state;
-	int ret;
 
 	crtc = analogix_dp_get_new_crtc(dp, old_state);
 	if (!crtc)
@@ -1147,11 +1137,7 @@ static void analogix_dp_bridge_atomic_pre_enable(struct drm_bridge *bridge,
 	if (old_crtc_state && old_crtc_state->self_refresh_active)
 		return;
 
-	if (dp->plat_data->panel) {
-		ret = drm_panel_prepare(dp->plat_data->panel);
-		if (ret)
-			DRM_ERROR("failed to prepare the panel ret = %d\n", ret);
-	}
+	drm_panel_prepare(dp->plat_data->panel);
 }
 
 static int analogix_dp_set_bridge(struct analogix_dp_device *dp)
@@ -1231,17 +1217,11 @@ static void analogix_dp_bridge_atomic_enable(struct drm_bridge *bridge,
 static void analogix_dp_bridge_disable(struct drm_bridge *bridge)
 {
 	struct analogix_dp_device *dp = bridge->driver_private;
-	int ret;
 
 	if (dp->dpms_mode != DRM_MODE_DPMS_ON)
 		return;
 
-	if (dp->plat_data->panel) {
-		if (drm_panel_disable(dp->plat_data->panel)) {
-			DRM_ERROR("failed to disable the panel\n");
-			return;
-		}
-	}
+	drm_panel_disable(dp->plat_data->panel);
 
 	disable_irq(dp->irq);
 
@@ -1249,11 +1229,7 @@ static void analogix_dp_bridge_disable(struct drm_bridge *bridge)
 
 	pm_runtime_put_sync(dp->dev);
 
-	if (dp->plat_data->panel) {
-		ret = drm_panel_unprepare(dp->plat_data->panel);
-		if (ret)
-			DRM_ERROR("failed to unprepare the panel ret = %d\n", ret);
-	}
+	drm_panel_unprepare(dp->plat_data->panel);
 
 	dp->fast_train_enable = false;
 	dp->psr_supported = false;
@@ -1678,10 +1654,7 @@ void analogix_dp_unbind(struct analogix_dp_device *dp)
 	analogix_dp_bridge_disable(dp->bridge);
 	dp->connector.funcs->destroy(&dp->connector);
 
-	if (dp->plat_data->panel) {
-		if (drm_panel_unprepare(dp->plat_data->panel))
-			DRM_ERROR("failed to turnoff the panel\n");
-	}
+	drm_panel_unprepare(dp->plat_data->panel);
 
 	drm_dp_aux_unregister(&dp->aux);
 

-- 
2.39.5

[PATCH 7/7] drm/panel: make prepare/enable and disable/unprepare calls return void

[Dmitry Baryshkov]

Now there are no users of the return value of the drm_panel_prepare(),
drm_panel_unprepare(), drm_panel_enable() and drm_panel_disable() calls.
Usually these calls are performed from the atomic callbacks, where it is
impossible to return an error. Stop returning error codes and return
void instead.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
---
 drivers/gpu/drm/drm_panel.c                     | 54 +++++++++----------------
 drivers/gpu/drm/panel/panel-newvision-nv3051d.c |  9 +----
 include/drm/drm_panel.h                         |  8 ++--
 3 files changed, 26 insertions(+), 45 deletions(-)

diff --git a/drivers/gpu/drm/drm_panel.c b/drivers/gpu/drm/drm_panel.c
index c627e42a7ce70459f50eb5095fffc806ca45dabf..faa7a76b63b53b3a45b3400d8bf3b58a027a340e 100644
--- a/drivers/gpu/drm/drm_panel.c
+++ b/drivers/gpu/drm/drm_panel.c
@@ -105,21 +105,21 @@ EXPORT_SYMBOL(drm_panel_remove);
  *
  * Calling this function will enable power and deassert any reset signals to
  * the panel. After this has completed it is possible to communicate with any
- * integrated circuitry via a command bus.
- *
- * Return: 0 on success or a negative error code on failure.
+ * integrated circuitry via a command bus. This function cannot fail (as it is
+ * called from the pre_enable call chain). There will always be a call to
+ * drm_panel_disable() afterwards.
  */
-int drm_panel_prepare(struct drm_panel *panel)
+void drm_panel_prepare(struct drm_panel *panel)
 {
 	struct drm_panel_follower *follower;
 	int ret;
 
 	if (!panel)
-		return -EINVAL;
+		return;
 
 	if (panel->prepared) {
 		dev_warn(panel->dev, "Skipping prepare of already prepared panel\n");
-		return 0;
+		return;
 	}
 
 	mutex_lock(&panel->follower_lock);
@@ -138,11 +138,8 @@ int drm_panel_prepare(struct drm_panel *panel)
 				 follower->funcs->panel_prepared, ret);
 	}
 
-	ret = 0;
 exit:
 	mutex_unlock(&panel->follower_lock);
-
-	return ret;
 }
 EXPORT_SYMBOL(drm_panel_prepare);
 
@@ -154,16 +151,14 @@ EXPORT_SYMBOL(drm_panel_prepare);
  * reset, turn off power supplies, ...). After this function has completed, it
  * is usually no longer possible to communicate with the panel until another
  * call to drm_panel_prepare().
- *
- * Return: 0 on success or a negative error code on failure.
  */
-int drm_panel_unprepare(struct drm_panel *panel)
+void drm_panel_unprepare(struct drm_panel *panel)
 {
 	struct drm_panel_follower *follower;
 	int ret;
 
 	if (!panel)
-		return -EINVAL;
+		return;
 
 	/*
 	 * If you are seeing the warning below it likely means one of two things:
@@ -176,7 +171,7 @@ int drm_panel_unprepare(struct drm_panel *panel)
 	 */
 	if (!panel->prepared) {
 		dev_warn(panel->dev, "Skipping unprepare of already unprepared panel\n");
-		return 0;
+		return;
 	}
 
 	mutex_lock(&panel->follower_lock);
@@ -195,11 +190,8 @@ int drm_panel_unprepare(struct drm_panel *panel)
 	}
 	panel->prepared = false;
 
-	ret = 0;
 exit:
 	mutex_unlock(&panel->follower_lock);
-
-	return ret;
 }
 EXPORT_SYMBOL(drm_panel_unprepare);
 
@@ -209,26 +201,26 @@ EXPORT_SYMBOL(drm_panel_unprepare);
  *
  * Calling this function will cause the panel display drivers to be turned on
  * and the backlight to be enabled. Content will be visible on screen after
- * this call completes.
- *
- * Return: 0 on success or a negative error code on failure.
+ * this call completes. This function cannot fail (as it is called from the
+ * enable call chain). There will always be a call to drm_panel_disable()
+ * afterwards.
  */
-int drm_panel_enable(struct drm_panel *panel)
+void drm_panel_enable(struct drm_panel *panel)
 {
 	int ret;
 
 	if (!panel)
-		return -EINVAL;
+		return;
 
 	if (panel->enabled) {
 		dev_warn(panel->dev, "Skipping enable of already enabled panel\n");
-		return 0;
+		return;
 	}
 
 	if (panel->funcs && panel->funcs->enable) {
 		ret = panel->funcs->enable(panel);
 		if (ret < 0)
-			return ret;
+			return;
 	}
 	panel->enabled = true;
 
@@ -236,8 +228,6 @@ int drm_panel_enable(struct drm_panel *panel)
 	if (ret < 0)
 		DRM_DEV_INFO(panel->dev, "failed to enable backlight: %d\n",
 			     ret);
-
-	return 0;
 }
 EXPORT_SYMBOL(drm_panel_enable);
 
@@ -248,15 +238,13 @@ EXPORT_SYMBOL(drm_panel_enable);
  * This will typically turn off the panel's backlight or disable the display
  * drivers. For smart panels it should still be possible to communicate with
  * the integrated circuitry via any command bus after this call.
- *
- * Return: 0 on success or a negative error code on failure.
  */
-int drm_panel_disable(struct drm_panel *panel)
+void drm_panel_disable(struct drm_panel *panel)
 {
 	int ret;
 
 	if (!panel)
-		return -EINVAL;
+		return;
 
 	/*
 	 * If you are seeing the warning below it likely means one of two things:
@@ -269,7 +257,7 @@ int drm_panel_disable(struct drm_panel *panel)
 	 */
 	if (!panel->enabled) {
 		dev_warn(panel->dev, "Skipping disable of already disabled panel\n");
-		return 0;
+		return;
 	}
 
 	ret = backlight_disable(panel->backlight);
@@ -280,11 +268,9 @@ int drm_panel_disable(struct drm_panel *panel)
 	if (panel->funcs && panel->funcs->disable) {
 		ret = panel->funcs->disable(panel);
 		if (ret < 0)
-			return ret;
+			return;
 	}
 	panel->enabled = false;
-
-	return 0;
 }
 EXPORT_SYMBOL(drm_panel_disable);
 
diff --git a/drivers/gpu/drm/panel/panel-newvision-nv3051d.c b/drivers/gpu/drm/panel/panel-newvision-nv3051d.c
index 5d115ecd5dd44c8e5e7d1fb8afe573324e987f59..b6429795e8f518646443dd8179f3ec28cef4dc0f 100644
--- a/drivers/gpu/drm/panel/panel-newvision-nv3051d.c
+++ b/drivers/gpu/drm/panel/panel-newvision-nv3051d.c
@@ -413,15 +413,10 @@ static int panel_nv3051d_probe(struct mipi_dsi_device *dsi)
 static void panel_nv3051d_shutdown(struct mipi_dsi_device *dsi)
 {
 	struct panel_nv3051d *ctx = mipi_dsi_get_drvdata(dsi);
-	int ret;
 
-	ret = drm_panel_unprepare(&ctx->panel);
-	if (ret < 0)
-		dev_err(&dsi->dev, "Failed to unprepare panel: %d\n", ret);
+	drm_panel_unprepare(&ctx->panel);
 
-	ret = drm_panel_disable(&ctx->panel);
-	if (ret < 0)
-		dev_err(&dsi->dev, "Failed to disable panel: %d\n", ret);
+	drm_panel_disable(&ctx->panel);
 }
 
 static void panel_nv3051d_remove(struct mipi_dsi_device *dsi)
diff --git a/include/drm/drm_panel.h b/include/drm/drm_panel.h
index a9c042c8dea1a82ef979c7a68204e0b55483fc28..18bf338c8b96254dc3f2880106b944e71ea4c9a7 100644
--- a/include/drm/drm_panel.h
+++ b/include/drm/drm_panel.h
@@ -275,11 +275,11 @@ void drm_panel_init(struct drm_panel *panel, struct device *dev,
 void drm_panel_add(struct drm_panel *panel);
 void drm_panel_remove(struct drm_panel *panel);
 
-int drm_panel_prepare(struct drm_panel *panel);
-int drm_panel_unprepare(struct drm_panel *panel);
+void drm_panel_prepare(struct drm_panel *panel);
+void drm_panel_unprepare(struct drm_panel *panel);
 
-int drm_panel_enable(struct drm_panel *panel);
-int drm_panel_disable(struct drm_panel *panel);
+void drm_panel_enable(struct drm_panel *panel);
+void drm_panel_disable(struct drm_panel *panel);
 
 int drm_panel_get_modes(struct drm_panel *panel, struct drm_connector *connector);
 

-- 
2.39.5

Re: [PATCH 7/7] drm/panel: make prepare/enable and disable/unprepare calls return void

[Neil Armstrong]

On 01/04/2025 07:11, Dmitry Baryshkov wrote:
> Now there are no users of the return value of the drm_panel_prepare(),
> drm_panel_unprepare(), drm_panel_enable() and drm_panel_disable() calls.
> Usually these calls are performed from the atomic callbacks, where it is
> impossible to return an error. Stop returning error codes and return
> void instead.
> 
> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
> ---
>   drivers/gpu/drm/drm_panel.c                     | 54 +++++++++----------------
>   drivers/gpu/drm/panel/panel-newvision-nv3051d.c |  9 +----
>   include/drm/drm_panel.h                         |  8 ++--
>   3 files changed, 26 insertions(+), 45 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_panel.c b/drivers/gpu/drm/drm_panel.c
> index c627e42a7ce70459f50eb5095fffc806ca45dabf..faa7a76b63b53b3a45b3400d8bf3b58a027a340e 100644
> --- a/drivers/gpu/drm/drm_panel.c
> +++ b/drivers/gpu/drm/drm_panel.c
> @@ -105,21 +105,21 @@ EXPORT_SYMBOL(drm_panel_remove);
>    *
>    * Calling this function will enable power and deassert any reset signals to
>    * the panel. After this has completed it is possible to communicate with any
> - * integrated circuitry via a command bus.
> - *
> - * Return: 0 on success or a negative error code on failure.
> + * integrated circuitry via a command bus. This function cannot fail (as it is
> + * called from the pre_enable call chain). There will always be a call to
> + * drm_panel_disable() afterwards.
>    */
> -int drm_panel_prepare(struct drm_panel *panel)
> +void drm_panel_prepare(struct drm_panel *panel)
>   {
>   	struct drm_panel_follower *follower;
>   	int ret;
>   
>   	if (!panel)
> -		return -EINVAL;
> +		return;
>   
>   	if (panel->prepared) {
>   		dev_warn(panel->dev, "Skipping prepare of already prepared panel\n");
> -		return 0;
> +		return;
>   	}
>   
>   	mutex_lock(&panel->follower_lock);
> @@ -138,11 +138,8 @@ int drm_panel_prepare(struct drm_panel *panel)
>   				 follower->funcs->panel_prepared, ret);
>   	}
>   
> -	ret = 0;
>   exit:
>   	mutex_unlock(&panel->follower_lock);
> -
> -	return ret;
>   }
>   EXPORT_SYMBOL(drm_panel_prepare);
>   
> @@ -154,16 +151,14 @@ EXPORT_SYMBOL(drm_panel_prepare);
>    * reset, turn off power supplies, ...). After this function has completed, it
>    * is usually no longer possible to communicate with the panel until another
>    * call to drm_panel_prepare().
> - *
> - * Return: 0 on success or a negative error code on failure.
>    */
> -int drm_panel_unprepare(struct drm_panel *panel)
> +void drm_panel_unprepare(struct drm_panel *panel)
>   {
>   	struct drm_panel_follower *follower;
>   	int ret;
>   
>   	if (!panel)
> -		return -EINVAL;
> +		return;
>   
>   	/*
>   	 * If you are seeing the warning below it likely means one of two things:
> @@ -176,7 +171,7 @@ int drm_panel_unprepare(struct drm_panel *panel)
>   	 */
>   	if (!panel->prepared) {
>   		dev_warn(panel->dev, "Skipping unprepare of already unprepared panel\n");
> -		return 0;
> +		return;
>   	}
>   
>   	mutex_lock(&panel->follower_lock);
> @@ -195,11 +190,8 @@ int drm_panel_unprepare(struct drm_panel *panel)
>   	}
>   	panel->prepared = false;
>   
> -	ret = 0;
>   exit:
>   	mutex_unlock(&panel->follower_lock);
> -
> -	return ret;
>   }
>   EXPORT_SYMBOL(drm_panel_unprepare);
>   
> @@ -209,26 +201,26 @@ EXPORT_SYMBOL(drm_panel_unprepare);
>    *
>    * Calling this function will cause the panel display drivers to be turned on
>    * and the backlight to be enabled. Content will be visible on screen after
> - * this call completes.
> - *
> - * Return: 0 on success or a negative error code on failure.
> + * this call completes. This function cannot fail (as it is called from the
> + * enable call chain). There will always be a call to drm_panel_disable()
> + * afterwards.
>    */
> -int drm_panel_enable(struct drm_panel *panel)
> +void drm_panel_enable(struct drm_panel *panel)
>   {
>   	int ret;
>   
>   	if (!panel)
> -		return -EINVAL;
> +		return;
>   
>   	if (panel->enabled) {
>   		dev_warn(panel->dev, "Skipping enable of already enabled panel\n");
> -		return 0;
> +		return;
>   	}
>   
>   	if (panel->funcs && panel->funcs->enable) {
>   		ret = panel->funcs->enable(panel);
>   		if (ret < 0)
> -			return ret;
> +			return;
>   	}
>   	panel->enabled = true;
>   
> @@ -236,8 +228,6 @@ int drm_panel_enable(struct drm_panel *panel)
>   	if (ret < 0)
>   		DRM_DEV_INFO(panel->dev, "failed to enable backlight: %d\n",
>   			     ret);
> -
> -	return 0;
>   }
>   EXPORT_SYMBOL(drm_panel_enable);
>   
> @@ -248,15 +238,13 @@ EXPORT_SYMBOL(drm_panel_enable);
>    * This will typically turn off the panel's backlight or disable the display
>    * drivers. For smart panels it should still be possible to communicate with
>    * the integrated circuitry via any command bus after this call.
> - *
> - * Return: 0 on success or a negative error code on failure.
>    */
> -int drm_panel_disable(struct drm_panel *panel)
> +void drm_panel_disable(struct drm_panel *panel)
>   {
>   	int ret;
>   
>   	if (!panel)
> -		return -EINVAL;
> +		return;
>   
>   	/*
>   	 * If you are seeing the warning below it likely means one of two things:
> @@ -269,7 +257,7 @@ int drm_panel_disable(struct drm_panel *panel)
>   	 */
>   	if (!panel->enabled) {
>   		dev_warn(panel->dev, "Skipping disable of already disabled panel\n");
> -		return 0;
> +		return;
>   	}
>   
>   	ret = backlight_disable(panel->backlight);
> @@ -280,11 +268,9 @@ int drm_panel_disable(struct drm_panel *panel)
>   	if (panel->funcs && panel->funcs->disable) {
>   		ret = panel->funcs->disable(panel);
>   		if (ret < 0)
> -			return ret;
> +			return;
>   	}
>   	panel->enabled = false;
> -
> -	return 0;
>   }
>   EXPORT_SYMBOL(drm_panel_disable);
>   
> diff --git a/drivers/gpu/drm/panel/panel-newvision-nv3051d.c b/drivers/gpu/drm/panel/panel-newvision-nv3051d.c
> index 5d115ecd5dd44c8e5e7d1fb8afe573324e987f59..b6429795e8f518646443dd8179f3ec28cef4dc0f 100644
> --- a/drivers/gpu/drm/panel/panel-newvision-nv3051d.c
> +++ b/drivers/gpu/drm/panel/panel-newvision-nv3051d.c
> @@ -413,15 +413,10 @@ static int panel_nv3051d_probe(struct mipi_dsi_device *dsi)
>   static void panel_nv3051d_shutdown(struct mipi_dsi_device *dsi)
>   {
>   	struct panel_nv3051d *ctx = mipi_dsi_get_drvdata(dsi);
> -	int ret;
>   
> -	ret = drm_panel_unprepare(&ctx->panel);
> -	if (ret < 0)
> -		dev_err(&dsi->dev, "Failed to unprepare panel: %d\n", ret);
> +	drm_panel_unprepare(&ctx->panel);
>   
> -	ret = drm_panel_disable(&ctx->panel);
> -	if (ret < 0)
> -		dev_err(&dsi->dev, "Failed to disable panel: %d\n", ret);
> +	drm_panel_disable(&ctx->panel);
>   }
>   
>   static void panel_nv3051d_remove(struct mipi_dsi_device *dsi)
> diff --git a/include/drm/drm_panel.h b/include/drm/drm_panel.h
> index a9c042c8dea1a82ef979c7a68204e0b55483fc28..18bf338c8b96254dc3f2880106b944e71ea4c9a7 100644
> --- a/include/drm/drm_panel.h
> +++ b/include/drm/drm_panel.h
> @@ -275,11 +275,11 @@ void drm_panel_init(struct drm_panel *panel, struct device *dev,
>   void drm_panel_add(struct drm_panel *panel);
>   void drm_panel_remove(struct drm_panel *panel);
>   
> -int drm_panel_prepare(struct drm_panel *panel);
> -int drm_panel_unprepare(struct drm_panel *panel);
> +void drm_panel_prepare(struct drm_panel *panel);
> +void drm_panel_unprepare(struct drm_panel *panel);
>   
> -int drm_panel_enable(struct drm_panel *panel);
> -int drm_panel_disable(struct drm_panel *panel);
> +void drm_panel_enable(struct drm_panel *panel);
> +void drm_panel_disable(struct drm_panel *panel);
>   
>   int drm_panel_get_modes(struct drm_panel *panel, struct drm_connector *connector);
>   
> 

LGTM

Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>

Re: [PATCH 1/7] drm/bridge: analogix_dp: drop extra calls to analogix_dp_prepare_panel()

[Damon Ding]

Hi Dmitry,

On 2025/4/1 13:11, Dmitry Baryshkov wrote:
> The analogix_dp_prepare_panel() returns immediately if there is no
> attached panel. Drop several calls to this function which are performed
> when dp->plat_data->panel is NULL.
> 
> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
> ---
>   drivers/gpu/drm/bridge/analogix/analogix_dp_core.c | 22 +---------------------
>   1 file changed, 1 insertion(+), 21 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> index 042154e2d8ccd74ac2dc27fe527e810a50e08a09..ab1cfc340aa95bbf13fe021bd33227b565a5458d 100644
> --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> @@ -1005,17 +1005,11 @@ static int analogix_dp_get_modes(struct drm_connector *connector)
>   {
>   	struct analogix_dp_device *dp = to_dp(connector);
>   	const struct drm_edid *drm_edid;
> -	int ret, num_modes = 0;
> +	int num_modes = 0;
>   
>   	if (dp->plat_data->panel) {
>   		num_modes += drm_panel_get_modes(dp->plat_data->panel, connector);
>   	} else {
> -		ret = analogix_dp_prepare_panel(dp, true, false);
> -		if (ret) {
> -			DRM_ERROR("Failed to prepare panel (%d)\n", ret);
> -			return 0;
> -		}
> -
>   		drm_edid = drm_edid_read_ddc(connector, &dp->aux.ddc);
>   
>   		drm_edid_connector_update(&dp->connector, drm_edid);
> @@ -1024,10 +1018,6 @@ static int analogix_dp_get_modes(struct drm_connector *connector)
>   			num_modes += drm_edid_connector_add_modes(&dp->connector);
>   			drm_edid_free(drm_edid);
>   		}
> -
> -		ret = analogix_dp_prepare_panel(dp, false, false);
> -		if (ret)
> -			DRM_ERROR("Failed to unprepare panel (%d)\n", ret);
>   	}
>   
>   	if (dp->plat_data->get_modes)
> @@ -1087,19 +1077,9 @@ analogix_dp_detect(struct drm_connector *connector, bool force)
>   	if (dp->plat_data->panel)
>   		return connector_status_connected;
>   
> -	ret = analogix_dp_prepare_panel(dp, true, false);
> -	if (ret) {
> -		DRM_ERROR("Failed to prepare panel (%d)\n", ret);
> -		return connector_status_disconnected;
> -	}
> -
>   	if (!analogix_dp_detect_hpd(dp))
>   		status = connector_status_connected;
>   
> -	ret = analogix_dp_prepare_panel(dp, false, false);
> -	if (ret)
> -		DRM_ERROR("Failed to unprepare panel (%d)\n", ret);
> -
>   	return status;
>   }
>   
> 

With the patch series:
https://patchwork.kernel.org/project/linux-rockchip/list/?series=942183

When I verify this patch, there will be a small warning:
drivers/gpu/drm/bridge/analogix/analogix_dp_core.c:1075:6: warning: 
unused variable 'ret' [-Wunused-variable]
         int ret;
             ^

It should be better to remove the unused 'ret'.

Best regards,
Damon

Re: [PATCH 2/7] drm/bridge: analogix_dp: drop unused argument to analogix_dp_prepare_panel()

[Damon Ding]

Hi Dmitry,

On 2025/4/1 13:11, Dmitry Baryshkov wrote:
> After previous cleanup all calling sites pass true as is_modeset_prepare
> argument to analogix_dp_prepare_panel(). Drop dead code depending on
> that argument being false.
> 
> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
> ---
>   drivers/gpu/drm/bridge/analogix/analogix_dp_core.c | 19 +++++--------------
>   1 file changed, 5 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> index ab1cfc340aa95bbf13fe021bd33227b565a5458d..82dc4b01806f9728dc882b0128171838e81f21b0 100644
> --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> @@ -963,13 +963,13 @@ static int analogix_dp_disable_psr(struct analogix_dp_device *dp)
>    * If @prepare is true, this function will prepare the panel. Conversely, if it
>    * is false, the panel will be unprepared.
>    *
> - * If @is_modeset_prepare is true, the function will disregard the current state
> + * The function will disregard the current state
>    * of the panel and either prepare/unprepare the panel based on @prepare. Once
>    * it finishes, it will update dp->panel_is_modeset to reflect the current state
>    * of the panel.
>    */
>   static int analogix_dp_prepare_panel(struct analogix_dp_device *dp,
> -				     bool prepare, bool is_modeset_prepare)
> +				     bool prepare)
>   {
>   	int ret = 0;
>   
> @@ -978,13 +978,6 @@ static int analogix_dp_prepare_panel(struct analogix_dp_device *dp,
>   
>   	mutex_lock(&dp->panel_lock);
>   
> -	/*
> -	 * Exit early if this is a temporary prepare/unprepare and we're already
> -	 * modeset (since we neither want to prepare twice or unprepare early).
> -	 */
> -	if (dp->panel_is_modeset && !is_modeset_prepare)
> -		goto out;
> -
>   	if (prepare)
>   		ret = drm_panel_prepare(dp->plat_data->panel);
>   	else
> @@ -993,8 +986,7 @@ static int analogix_dp_prepare_panel(struct analogix_dp_device *dp,
>   	if (ret)
>   		goto out;
>   
> -	if (is_modeset_prepare)
> -		dp->panel_is_modeset = prepare;
> +	dp->panel_is_modeset = prepare;
>   
>   out:
>   	mutex_unlock(&dp->panel_lock);
> @@ -1072,7 +1064,6 @@ analogix_dp_detect(struct drm_connector *connector, bool force)
>   {
>   	struct analogix_dp_device *dp = to_dp(connector);
>   	enum drm_connector_status status = connector_status_disconnected;
> -	int ret;
>   
>   	if (dp->plat_data->panel)
>   		return connector_status_connected;
> @@ -1194,7 +1185,7 @@ static void analogix_dp_bridge_atomic_pre_enable(struct drm_bridge *bridge,
>   	if (old_crtc_state && old_crtc_state->self_refresh_active)
>   		return;
>   
> -	ret = analogix_dp_prepare_panel(dp, true, true);
> +	ret = analogix_dp_prepare_panel(dp, true);
>   	if (ret)
>   		DRM_ERROR("failed to setup the panel ret = %d\n", ret);
>   }
> @@ -1294,7 +1285,7 @@ static void analogix_dp_bridge_disable(struct drm_bridge *bridge)
>   
>   	pm_runtime_put_sync(dp->dev);
>   
> -	ret = analogix_dp_prepare_panel(dp, false, true);
> +	ret = analogix_dp_prepare_panel(dp, false);
>   	if (ret)
>   		DRM_ERROR("failed to setup the panel ret = %d\n", ret);
>   
> 

The patch has been verified with the eDP panel "lg,lp079qx1-sp0v" in 
RK3588S EVB1 board.

Tested-by: Damon Ding <damon.ding@rock-chips.com>

Best regards,
Damon

Re: [PATCH 3/7] drm/bridge: analogic_dp: drop panel_is_modeset

[Damon Ding]

Hi Dmitry,

On 2025/4/1 13:11, Dmitry Baryshkov wrote:
> The dp->panel_is_modeset is now a write-only field. Drop it completely.
> 
> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
> ---
>   drivers/gpu/drm/bridge/analogix/analogix_dp_core.c | 11 +----------
>   drivers/gpu/drm/bridge/analogix/analogix_dp_core.h |  1 -
>   2 files changed, 1 insertion(+), 11 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> index 82dc4b01806f9728dc882b0128171838e81f21b0..704c6169116eb2601d2ad02dc7294455ceff5460 100644
> --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> @@ -964,9 +964,7 @@ static int analogix_dp_disable_psr(struct analogix_dp_device *dp)
>    * is false, the panel will be unprepared.
>    *
>    * The function will disregard the current state
> - * of the panel and either prepare/unprepare the panel based on @prepare. Once
> - * it finishes, it will update dp->panel_is_modeset to reflect the current state
> - * of the panel.
> + * of the panel and either prepare/unprepare the panel based on @prepare.
>    */
>   static int analogix_dp_prepare_panel(struct analogix_dp_device *dp,
>   				     bool prepare)
> @@ -983,12 +981,6 @@ static int analogix_dp_prepare_panel(struct analogix_dp_device *dp,
>   	else
>   		ret = drm_panel_unprepare(dp->plat_data->panel);
>   
> -	if (ret)
> -		goto out;
> -
> -	dp->panel_is_modeset = prepare;
> -
> -out:
>   	mutex_unlock(&dp->panel_lock);
>   	return ret;
>   }
> @@ -1532,7 +1524,6 @@ analogix_dp_probe(struct device *dev, struct analogix_dp_plat_data *plat_data)
>   	dp->dpms_mode = DRM_MODE_DPMS_OFF;
>   
>   	mutex_init(&dp->panel_lock);
> -	dp->panel_is_modeset = false;
>   
>   	/*
>   	 * platform dp driver need containor_of the plat_data to get
> diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
> index 774d11574b095b093ddf2818ad5b84be6605c9bf..b679d5b71d276f458d905c936160f107225bc6c5 100644
> --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
> +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
> @@ -170,7 +170,6 @@ struct analogix_dp_device {
>   	bool			psr_supported;
>   
>   	struct mutex		panel_lock;
> -	bool			panel_is_modeset;
>   
>   	struct analogix_dp_plat_data *plat_data;
>   };
> 

The patch has been verified with the eDP panel "lg,lp079qx1-sp0v" in 
RK3588S EVB1 board.

Tested-by: Damon Ding <damon.ding@rock-chips.com>

Best regards,
Damon

Re: [PATCH 4/7] drm/bridge: analogic_dp: drop panel_lock

[Damon Ding]

Hi Dmitry,

On 2025/4/1 13:11, Dmitry Baryshkov wrote:
> The analogix_dp_prepare_panel() function is called from bridge's
> atomic_pre_enable() and atomic_post_disable() callbacks, which can not
> happen simultaneously. Drop the useless mutex.
> 
> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
> ---
>   drivers/gpu/drm/bridge/analogix/analogix_dp_core.c | 5 -----
>   drivers/gpu/drm/bridge/analogix/analogix_dp_core.h | 2 --
>   2 files changed, 7 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> index 704c6169116eb2601d2ad02dc7294455ceff5460..1ec4d277fe6bb03ad9eb8451ae2af5ad5ada0978 100644
> --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> @@ -974,14 +974,11 @@ static int analogix_dp_prepare_panel(struct analogix_dp_device *dp,
>   	if (!dp->plat_data->panel)
>   		return 0;
>   
> -	mutex_lock(&dp->panel_lock);
> -
>   	if (prepare)
>   		ret = drm_panel_prepare(dp->plat_data->panel);
>   	else
>   		ret = drm_panel_unprepare(dp->plat_data->panel);
>   
> -	mutex_unlock(&dp->panel_lock);
>   	return ret;
>   }
>   
> @@ -1523,8 +1520,6 @@ analogix_dp_probe(struct device *dev, struct analogix_dp_plat_data *plat_data)
>   	dp->dev = &pdev->dev;
>   	dp->dpms_mode = DRM_MODE_DPMS_OFF;
>   
> -	mutex_init(&dp->panel_lock);
> -
>   	/*
>   	 * platform dp driver need containor_of the plat_data to get
>   	 * the driver private data, so we need to store the point of
> diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
> index b679d5b71d276f458d905c936160f107225bc6c5..2b54120ba4a3ef55af518a0629a5c8469f275a0f 100644
> --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
> +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
> @@ -169,8 +169,6 @@ struct analogix_dp_device {
>   	bool			fast_train_enable;
>   	bool			psr_supported;
>   
> -	struct mutex		panel_lock;
> -
>   	struct analogix_dp_plat_data *plat_data;
>   };
>   
> 

The patch has been verified with the eDP panel "lg,lp079qx1-sp0v" in 
RK3588S EVB1 board.

Tested-by: Damon Ding <damon.ding@rock-chips.com>

Best regards,
Damon

Re: [PATCH 5/7] drm/bridge: analogix_dp: inline analogix_dp_prepare_panel()

[Damon Ding]

Hi Dmitry,

On 2025/4/1 13:11, Dmitry Baryshkov wrote:
> The analogix_dp_prepare_panel() is now only calling a corresponding
> drm_panel function. Inline it to simplify the code.
> 
> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
> ---
>   drivers/gpu/drm/bridge/analogix/analogix_dp_core.c | 43 +++++-----------------
>   1 file changed, 10 insertions(+), 33 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> index 1ec4d277fe6bb03ad9eb8451ae2af5ad5ada0978..f60068011008482f7b7b2edfcab5fb1b3e9e130f 100644
> --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> @@ -955,33 +955,6 @@ static int analogix_dp_disable_psr(struct analogix_dp_device *dp)
>   	return analogix_dp_send_psr_spd(dp, &psr_vsc, true);
>   }
>   
> -/*
> - * This function is a bit of a catch-all for panel preparation, hopefully
> - * simplifying the logic of functions that need to prepare/unprepare the panel
> - * below.
> - *
> - * If @prepare is true, this function will prepare the panel. Conversely, if it
> - * is false, the panel will be unprepared.
> - *
> - * The function will disregard the current state
> - * of the panel and either prepare/unprepare the panel based on @prepare.
> - */
> -static int analogix_dp_prepare_panel(struct analogix_dp_device *dp,
> -				     bool prepare)
> -{
> -	int ret = 0;
> -
> -	if (!dp->plat_data->panel)
> -		return 0;
> -
> -	if (prepare)
> -		ret = drm_panel_prepare(dp->plat_data->panel);
> -	else
> -		ret = drm_panel_unprepare(dp->plat_data->panel);
> -
> -	return ret;
> -}
> -
>   static int analogix_dp_get_modes(struct drm_connector *connector)
>   {
>   	struct analogix_dp_device *dp = to_dp(connector);
> @@ -1174,9 +1147,11 @@ static void analogix_dp_bridge_atomic_pre_enable(struct drm_bridge *bridge,
>   	if (old_crtc_state && old_crtc_state->self_refresh_active)
>   		return;
>   
> -	ret = analogix_dp_prepare_panel(dp, true);
> -	if (ret)
> -		DRM_ERROR("failed to setup the panel ret = %d\n", ret);
> +	if (dp->plat_data->panel) {
> +		ret = drm_panel_prepare(dp->plat_data->panel);
> +		if (ret)
> +			DRM_ERROR("failed to prepare the panel ret = %d\n", ret);
> +	}
>   }
>   
>   static int analogix_dp_set_bridge(struct analogix_dp_device *dp)
> @@ -1274,9 +1249,11 @@ static void analogix_dp_bridge_disable(struct drm_bridge *bridge)
>   
>   	pm_runtime_put_sync(dp->dev);
>   
> -	ret = analogix_dp_prepare_panel(dp, false);
> -	if (ret)
> -		DRM_ERROR("failed to setup the panel ret = %d\n", ret);
> +	if (dp->plat_data->panel) {
> +		ret = drm_panel_unprepare(dp->plat_data->panel);
> +		if (ret)
> +			DRM_ERROR("failed to unprepare the panel ret = %d\n", ret);
> +	}
>   
>   	dp->fast_train_enable = false;
>   	dp->psr_supported = false;
> 

The patch has been verified with the eDP panel "lg,lp079qx1-sp0v" in 
RK3588S EVB1 board.

Tested-by: Damon Ding <damon.ding@rock-chips.com>

Best regards,
Damon

Re: [PATCH 6/7] drm/bridge: analogix_dp: ignore return values of drm_panel_* calls

[Damon Ding]

Hi Dmitry,

On 2025/4/1 13:11, Dmitry Baryshkov wrote:
> Follow the example of other drivers and ignore return values of the
> drm_panel_prepare() / unprepare() / enable() / disable() calls. There is
> no possible error recovery, so the driver just logs a message.
> 
> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
> ---
>   drivers/gpu/drm/bridge/analogix/analogix_dp_core.c | 39 ++++------------------
>   1 file changed, 6 insertions(+), 33 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> index f60068011008482f7b7b2edfcab5fb1b3e9e130f..c7dffdae31877ae194fc6b0a5bf21be203f7dcc4 100644
> --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> @@ -838,10 +838,7 @@ static int analogix_dp_commit(struct analogix_dp_device *dp)
>   	int ret;
>   
>   	/* Keep the panel disabled while we configure video */
> -	if (dp->plat_data->panel) {
> -		if (drm_panel_disable(dp->plat_data->panel))
> -			DRM_ERROR("failed to disable the panel\n");
> -	}
> +	drm_panel_disable(dp->plat_data->panel);
>   
>   	ret = analogix_dp_train_link(dp);
>   	if (ret) {
> @@ -863,13 +860,7 @@ static int analogix_dp_commit(struct analogix_dp_device *dp)
>   	}
>   
>   	/* Safe to enable the panel now */
> -	if (dp->plat_data->panel) {
> -		ret = drm_panel_enable(dp->plat_data->panel);
> -		if (ret) {
> -			DRM_ERROR("failed to enable the panel\n");
> -			return ret;
> -		}
> -	}
> +	drm_panel_enable(dp->plat_data->panel);
>   
>   	/* Check whether panel supports fast training */
>   	ret = analogix_dp_fast_link_train_detection(dp);
> @@ -1136,7 +1127,6 @@ static void analogix_dp_bridge_atomic_pre_enable(struct drm_bridge *bridge,
>   	struct analogix_dp_device *dp = bridge->driver_private;
>   	struct drm_crtc *crtc;
>   	struct drm_crtc_state *old_crtc_state;
> -	int ret;
>   
>   	crtc = analogix_dp_get_new_crtc(dp, old_state);
>   	if (!crtc)
> @@ -1147,11 +1137,7 @@ static void analogix_dp_bridge_atomic_pre_enable(struct drm_bridge *bridge,
>   	if (old_crtc_state && old_crtc_state->self_refresh_active)
>   		return;
>   
> -	if (dp->plat_data->panel) {
> -		ret = drm_panel_prepare(dp->plat_data->panel);
> -		if (ret)
> -			DRM_ERROR("failed to prepare the panel ret = %d\n", ret);
> -	}
> +	drm_panel_prepare(dp->plat_data->panel);
>   }
>   
>   static int analogix_dp_set_bridge(struct analogix_dp_device *dp)
> @@ -1231,17 +1217,11 @@ static void analogix_dp_bridge_atomic_enable(struct drm_bridge *bridge,
>   static void analogix_dp_bridge_disable(struct drm_bridge *bridge)
>   {
>   	struct analogix_dp_device *dp = bridge->driver_private;
> -	int ret;
>   
>   	if (dp->dpms_mode != DRM_MODE_DPMS_ON)
>   		return;
>   
> -	if (dp->plat_data->panel) {
> -		if (drm_panel_disable(dp->plat_data->panel)) {
> -			DRM_ERROR("failed to disable the panel\n");
> -			return;
> -		}
> -	}
> +	drm_panel_disable(dp->plat_data->panel);
>   
>   	disable_irq(dp->irq);
>   
> @@ -1249,11 +1229,7 @@ static void analogix_dp_bridge_disable(struct drm_bridge *bridge)
>   
>   	pm_runtime_put_sync(dp->dev);
>   
> -	if (dp->plat_data->panel) {
> -		ret = drm_panel_unprepare(dp->plat_data->panel);
> -		if (ret)
> -			DRM_ERROR("failed to unprepare the panel ret = %d\n", ret);
> -	}
> +	drm_panel_unprepare(dp->plat_data->panel);
>   
>   	dp->fast_train_enable = false;
>   	dp->psr_supported = false;
> @@ -1678,10 +1654,7 @@ void analogix_dp_unbind(struct analogix_dp_device *dp)
>   	analogix_dp_bridge_disable(dp->bridge);
>   	dp->connector.funcs->destroy(&dp->connector);
>   
> -	if (dp->plat_data->panel) {
> -		if (drm_panel_unprepare(dp->plat_data->panel))
> -			DRM_ERROR("failed to turnoff the panel\n");
> -	}
> +	drm_panel_unprepare(dp->plat_data->panel);
>   
>   	drm_dp_aux_unregister(&dp->aux);
>   
> 

The patch has been verified with the eDP panel "lg,lp079qx1-sp0v" in 
RK3588S EVB1 board.

Tested-by: Damon Ding <damon.ding@rock-chips.com>

Best regards,
Damon

Re: [PATCH 1/7] drm/bridge: analogix_dp: drop extra calls to analogix_dp_prepare_panel()

[Damon Ding]

On 2025/4/14 9:20, Damon Ding wrote:
> Hi Dmitry,
> 
> On 2025/4/1 13:11, Dmitry Baryshkov wrote:
>> The analogix_dp_prepare_panel() returns immediately if there is no
>> attached panel. Drop several calls to this function which are performed
>> when dp->plat_data->panel is NULL.
>>
>> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
>> ---
>>   drivers/gpu/drm/bridge/analogix/analogix_dp_core.c | 22 
>> +---------------------
>>   1 file changed, 1 insertion(+), 21 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/ 
>> drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
>> index 
>> 042154e2d8ccd74ac2dc27fe527e810a50e08a09..ab1cfc340aa95bbf13fe021bd33227b565a5458d 100644
>> --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
>> +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
>> @@ -1005,17 +1005,11 @@ static int analogix_dp_get_modes(struct 
>> drm_connector *connector)
>>   {
>>       struct analogix_dp_device *dp = to_dp(connector);
>>       const struct drm_edid *drm_edid;
>> -    int ret, num_modes = 0;
>> +    int num_modes = 0;
>>       if (dp->plat_data->panel) {
>>           num_modes += drm_panel_get_modes(dp->plat_data->panel, 
>> connector);
>>       } else {
>> -        ret = analogix_dp_prepare_panel(dp, true, false);
>> -        if (ret) {
>> -            DRM_ERROR("Failed to prepare panel (%d)\n", ret);
>> -            return 0;
>> -        }
>> -
>>           drm_edid = drm_edid_read_ddc(connector, &dp->aux.ddc);
>>           drm_edid_connector_update(&dp->connector, drm_edid);
>> @@ -1024,10 +1018,6 @@ static int analogix_dp_get_modes(struct 
>> drm_connector *connector)
>>               num_modes += drm_edid_connector_add_modes(&dp->connector);
>>               drm_edid_free(drm_edid);
>>           }
>> -
>> -        ret = analogix_dp_prepare_panel(dp, false, false);
>> -        if (ret)
>> -            DRM_ERROR("Failed to unprepare panel (%d)\n", ret);
>>       }
>>       if (dp->plat_data->get_modes)
>> @@ -1087,19 +1077,9 @@ analogix_dp_detect(struct drm_connector 
>> *connector, bool force)
>>       if (dp->plat_data->panel)
>>           return connector_status_connected;
>> -    ret = analogix_dp_prepare_panel(dp, true, false);
>> -    if (ret) {
>> -        DRM_ERROR("Failed to prepare panel (%d)\n", ret);
>> -        return connector_status_disconnected;
>> -    }
>> -
>>       if (!analogix_dp_detect_hpd(dp))
>>           status = connector_status_connected;
>> -    ret = analogix_dp_prepare_panel(dp, false, false);
>> -    if (ret)
>> -        DRM_ERROR("Failed to unprepare panel (%d)\n", ret);
>> -
>>       return status;
>>   }
>>
> 
> With the patch series:
> https://patchwork.kernel.org/project/linux-rockchip/list/?series=942183
> 
> When I verify this patch, there will be a small warning:
> drivers/gpu/drm/bridge/analogix/analogix_dp_core.c:1075:6: warning: 
> unused variable 'ret' [-Wunused-variable]
>          int ret;
>              ^
> 
> It should be better to remove the unused 'ret'.
> 
> Best regards,
> Damon
> 
> 
> 

Tested-by: Damon Ding <damon.ding@rock-chips.com>

Re: [PATCH 1/7] drm/bridge: analogix_dp: drop extra calls to analogix_dp_prepare_panel()

[Neil Armstrong]

On 01/04/2025 07:11, Dmitry Baryshkov wrote:
> The analogix_dp_prepare_panel() returns immediately if there is no
> attached panel. Drop several calls to this function which are performed
> when dp->plat_data->panel is NULL.
> 
> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
> ---
>   drivers/gpu/drm/bridge/analogix/analogix_dp_core.c | 22 +---------------------
>   1 file changed, 1 insertion(+), 21 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> index 042154e2d8ccd74ac2dc27fe527e810a50e08a09..ab1cfc340aa95bbf13fe021bd33227b565a5458d 100644
> --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> @@ -1005,17 +1005,11 @@ static int analogix_dp_get_modes(struct drm_connector *connector)
>   {
>   	struct analogix_dp_device *dp = to_dp(connector);
>   	const struct drm_edid *drm_edid;
> -	int ret, num_modes = 0;
> +	int num_modes = 0;
>   
>   	if (dp->plat_data->panel) {
>   		num_modes += drm_panel_get_modes(dp->plat_data->panel, connector);
>   	} else {
> -		ret = analogix_dp_prepare_panel(dp, true, false);
> -		if (ret) {
> -			DRM_ERROR("Failed to prepare panel (%d)\n", ret);
> -			return 0;
> -		}
> -
>   		drm_edid = drm_edid_read_ddc(connector, &dp->aux.ddc);
>   
>   		drm_edid_connector_update(&dp->connector, drm_edid);
> @@ -1024,10 +1018,6 @@ static int analogix_dp_get_modes(struct drm_connector *connector)
>   			num_modes += drm_edid_connector_add_modes(&dp->connector);
>   			drm_edid_free(drm_edid);
>   		}
> -
> -		ret = analogix_dp_prepare_panel(dp, false, false);
> -		if (ret)
> -			DRM_ERROR("Failed to unprepare panel (%d)\n", ret);
>   	}
>   
>   	if (dp->plat_data->get_modes)
> @@ -1087,19 +1077,9 @@ analogix_dp_detect(struct drm_connector *connector, bool force)
>   	if (dp->plat_data->panel)
>   		return connector_status_connected;
>   
> -	ret = analogix_dp_prepare_panel(dp, true, false);
> -	if (ret) {
> -		DRM_ERROR("Failed to prepare panel (%d)\n", ret);
> -		return connector_status_disconnected;
> -	}
> -
>   	if (!analogix_dp_detect_hpd(dp))
>   		status = connector_status_connected;
>   
> -	ret = analogix_dp_prepare_panel(dp, false, false);
> -	if (ret)
> -		DRM_ERROR("Failed to unprepare panel (%d)\n", ret);
> -
>   	return status;
>   }
>   
> 

Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>

Re: [PATCH 2/7] drm/bridge: analogix_dp: drop unused argument to analogix_dp_prepare_panel()

[Neil Armstrong]

On 01/04/2025 07:11, Dmitry Baryshkov wrote:
> After previous cleanup all calling sites pass true as is_modeset_prepare
> argument to analogix_dp_prepare_panel(). Drop dead code depending on
> that argument being false.
> 
> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
> ---
>   drivers/gpu/drm/bridge/analogix/analogix_dp_core.c | 19 +++++--------------
>   1 file changed, 5 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> index ab1cfc340aa95bbf13fe021bd33227b565a5458d..82dc4b01806f9728dc882b0128171838e81f21b0 100644
> --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> @@ -963,13 +963,13 @@ static int analogix_dp_disable_psr(struct analogix_dp_device *dp)
>    * If @prepare is true, this function will prepare the panel. Conversely, if it
>    * is false, the panel will be unprepared.
>    *
> - * If @is_modeset_prepare is true, the function will disregard the current state
> + * The function will disregard the current state
>    * of the panel and either prepare/unprepare the panel based on @prepare. Once
>    * it finishes, it will update dp->panel_is_modeset to reflect the current state
>    * of the panel.
>    */
>   static int analogix_dp_prepare_panel(struct analogix_dp_device *dp,
> -				     bool prepare, bool is_modeset_prepare)
> +				     bool prepare)
>   {
>   	int ret = 0;
>   
> @@ -978,13 +978,6 @@ static int analogix_dp_prepare_panel(struct analogix_dp_device *dp,
>   
>   	mutex_lock(&dp->panel_lock);
>   
> -	/*
> -	 * Exit early if this is a temporary prepare/unprepare and we're already
> -	 * modeset (since we neither want to prepare twice or unprepare early).
> -	 */
> -	if (dp->panel_is_modeset && !is_modeset_prepare)
> -		goto out;
> -
>   	if (prepare)
>   		ret = drm_panel_prepare(dp->plat_data->panel);
>   	else
> @@ -993,8 +986,7 @@ static int analogix_dp_prepare_panel(struct analogix_dp_device *dp,
>   	if (ret)
>   		goto out;
>   
> -	if (is_modeset_prepare)
> -		dp->panel_is_modeset = prepare;
> +	dp->panel_is_modeset = prepare;
>   
>   out:
>   	mutex_unlock(&dp->panel_lock);
> @@ -1072,7 +1064,6 @@ analogix_dp_detect(struct drm_connector *connector, bool force)
>   {
>   	struct analogix_dp_device *dp = to_dp(connector);
>   	enum drm_connector_status status = connector_status_disconnected;
> -	int ret;
>   
>   	if (dp->plat_data->panel)
>   		return connector_status_connected;
> @@ -1194,7 +1185,7 @@ static void analogix_dp_bridge_atomic_pre_enable(struct drm_bridge *bridge,
>   	if (old_crtc_state && old_crtc_state->self_refresh_active)
>   		return;
>   
> -	ret = analogix_dp_prepare_panel(dp, true, true);
> +	ret = analogix_dp_prepare_panel(dp, true);
>   	if (ret)
>   		DRM_ERROR("failed to setup the panel ret = %d\n", ret);
>   }
> @@ -1294,7 +1285,7 @@ static void analogix_dp_bridge_disable(struct drm_bridge *bridge)
>   
>   	pm_runtime_put_sync(dp->dev);
>   
> -	ret = analogix_dp_prepare_panel(dp, false, true);
> +	ret = analogix_dp_prepare_panel(dp, false);
>   	if (ret)
>   		DRM_ERROR("failed to setup the panel ret = %d\n", ret);
>   
> 

Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>

Re: [PATCH 3/7] drm/bridge: analogic_dp: drop panel_is_modeset

[Neil Armstrong]

On 01/04/2025 07:11, Dmitry Baryshkov wrote:
> The dp->panel_is_modeset is now a write-only field. Drop it completely.
> 
> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
> ---
>   drivers/gpu/drm/bridge/analogix/analogix_dp_core.c | 11 +----------
>   drivers/gpu/drm/bridge/analogix/analogix_dp_core.h |  1 -
>   2 files changed, 1 insertion(+), 11 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> index 82dc4b01806f9728dc882b0128171838e81f21b0..704c6169116eb2601d2ad02dc7294455ceff5460 100644
> --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> @@ -964,9 +964,7 @@ static int analogix_dp_disable_psr(struct analogix_dp_device *dp)
>    * is false, the panel will be unprepared.
>    *
>    * The function will disregard the current state
> - * of the panel and either prepare/unprepare the panel based on @prepare. Once
> - * it finishes, it will update dp->panel_is_modeset to reflect the current state
> - * of the panel.
> + * of the panel and either prepare/unprepare the panel based on @prepare.
>    */
>   static int analogix_dp_prepare_panel(struct analogix_dp_device *dp,
>   				     bool prepare)
> @@ -983,12 +981,6 @@ static int analogix_dp_prepare_panel(struct analogix_dp_device *dp,
>   	else
>   		ret = drm_panel_unprepare(dp->plat_data->panel);
>   
> -	if (ret)
> -		goto out;
> -
> -	dp->panel_is_modeset = prepare;
> -
> -out:
>   	mutex_unlock(&dp->panel_lock);
>   	return ret;
>   }
> @@ -1532,7 +1524,6 @@ analogix_dp_probe(struct device *dev, struct analogix_dp_plat_data *plat_data)
>   	dp->dpms_mode = DRM_MODE_DPMS_OFF;
>   
>   	mutex_init(&dp->panel_lock);
> -	dp->panel_is_modeset = false;
>   
>   	/*
>   	 * platform dp driver need containor_of the plat_data to get
> diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
> index 774d11574b095b093ddf2818ad5b84be6605c9bf..b679d5b71d276f458d905c936160f107225bc6c5 100644
> --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
> +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
> @@ -170,7 +170,6 @@ struct analogix_dp_device {
>   	bool			psr_supported;
>   
>   	struct mutex		panel_lock;
> -	bool			panel_is_modeset;
>   
>   	struct analogix_dp_plat_data *plat_data;
>   };
> 

Re: [PATCH 4/7] drm/bridge: analogic_dp: drop panel_lock

[Neil Armstrong]

On 01/04/2025 07:11, Dmitry Baryshkov wrote:
> The analogix_dp_prepare_panel() function is called from bridge's
> atomic_pre_enable() and atomic_post_disable() callbacks, which can not
> happen simultaneously. Drop the useless mutex.
> 
> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
> ---
>   drivers/gpu/drm/bridge/analogix/analogix_dp_core.c | 5 -----
>   drivers/gpu/drm/bridge/analogix/analogix_dp_core.h | 2 --
>   2 files changed, 7 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> index 704c6169116eb2601d2ad02dc7294455ceff5460..1ec4d277fe6bb03ad9eb8451ae2af5ad5ada0978 100644
> --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> @@ -974,14 +974,11 @@ static int analogix_dp_prepare_panel(struct analogix_dp_device *dp,
>   	if (!dp->plat_data->panel)
>   		return 0;
>   
> -	mutex_lock(&dp->panel_lock);
> -
>   	if (prepare)
>   		ret = drm_panel_prepare(dp->plat_data->panel);
>   	else
>   		ret = drm_panel_unprepare(dp->plat_data->panel);
>   
> -	mutex_unlock(&dp->panel_lock);
>   	return ret;
>   }
>   
> @@ -1523,8 +1520,6 @@ analogix_dp_probe(struct device *dev, struct analogix_dp_plat_data *plat_data)
>   	dp->dev = &pdev->dev;
>   	dp->dpms_mode = DRM_MODE_DPMS_OFF;
>   
> -	mutex_init(&dp->panel_lock);
> -
>   	/*
>   	 * platform dp driver need containor_of the plat_data to get
>   	 * the driver private data, so we need to store the point of
> diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
> index b679d5b71d276f458d905c936160f107225bc6c5..2b54120ba4a3ef55af518a0629a5c8469f275a0f 100644
> --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
> +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
> @@ -169,8 +169,6 @@ struct analogix_dp_device {
>   	bool			fast_train_enable;
>   	bool			psr_supported;
>   
> -	struct mutex		panel_lock;
> -
>   	struct analogix_dp_plat_data *plat_data;
>   };
>   
> 

Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>

Re: [PATCH 5/7] drm/bridge: analogix_dp: inline analogix_dp_prepare_panel()

[Neil Armstrong]

On 01/04/2025 07:11, Dmitry Baryshkov wrote:
> The analogix_dp_prepare_panel() is now only calling a corresponding
> drm_panel function. Inline it to simplify the code.
> 
> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
> ---
>   drivers/gpu/drm/bridge/analogix/analogix_dp_core.c | 43 +++++-----------------
>   1 file changed, 10 insertions(+), 33 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> index 1ec4d277fe6bb03ad9eb8451ae2af5ad5ada0978..f60068011008482f7b7b2edfcab5fb1b3e9e130f 100644
> --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> @@ -955,33 +955,6 @@ static int analogix_dp_disable_psr(struct analogix_dp_device *dp)
>   	return analogix_dp_send_psr_spd(dp, &psr_vsc, true);
>   }
>   
> -/*
> - * This function is a bit of a catch-all for panel preparation, hopefully
> - * simplifying the logic of functions that need to prepare/unprepare the panel
> - * below.
> - *
> - * If @prepare is true, this function will prepare the panel. Conversely, if it
> - * is false, the panel will be unprepared.
> - *
> - * The function will disregard the current state
> - * of the panel and either prepare/unprepare the panel based on @prepare.
> - */
> -static int analogix_dp_prepare_panel(struct analogix_dp_device *dp,
> -				     bool prepare)
> -{
> -	int ret = 0;
> -
> -	if (!dp->plat_data->panel)
> -		return 0;
> -
> -	if (prepare)
> -		ret = drm_panel_prepare(dp->plat_data->panel);
> -	else
> -		ret = drm_panel_unprepare(dp->plat_data->panel);
> -
> -	return ret;
> -}
> -
>   static int analogix_dp_get_modes(struct drm_connector *connector)
>   {
>   	struct analogix_dp_device *dp = to_dp(connector);
> @@ -1174,9 +1147,11 @@ static void analogix_dp_bridge_atomic_pre_enable(struct drm_bridge *bridge,
>   	if (old_crtc_state && old_crtc_state->self_refresh_active)
>   		return;
>   
> -	ret = analogix_dp_prepare_panel(dp, true);
> -	if (ret)
> -		DRM_ERROR("failed to setup the panel ret = %d\n", ret);
> +	if (dp->plat_data->panel) {
> +		ret = drm_panel_prepare(dp->plat_data->panel);
> +		if (ret)
> +			DRM_ERROR("failed to prepare the panel ret = %d\n", ret);
> +	}
>   }
>   
>   static int analogix_dp_set_bridge(struct analogix_dp_device *dp)
> @@ -1274,9 +1249,11 @@ static void analogix_dp_bridge_disable(struct drm_bridge *bridge)
>   
>   	pm_runtime_put_sync(dp->dev);
>   
> -	ret = analogix_dp_prepare_panel(dp, false);
> -	if (ret)
> -		DRM_ERROR("failed to setup the panel ret = %d\n", ret);
> +	if (dp->plat_data->panel) {
> +		ret = drm_panel_unprepare(dp->plat_data->panel);
> +		if (ret)
> +			DRM_ERROR("failed to unprepare the panel ret = %d\n", ret);
> +	}
>   
>   	dp->fast_train_enable = false;
>   	dp->psr_supported = false;
> 

Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>

Re: [PATCH 6/7] drm/bridge: analogix_dp: ignore return values of drm_panel_* calls

[Neil Armstrong]

On 01/04/2025 07:11, Dmitry Baryshkov wrote:
> Follow the example of other drivers and ignore return values of the
> drm_panel_prepare() / unprepare() / enable() / disable() calls. There is
> no possible error recovery, so the driver just logs a message.
> 
> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
> ---
>   drivers/gpu/drm/bridge/analogix/analogix_dp_core.c | 39 ++++------------------
>   1 file changed, 6 insertions(+), 33 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> index f60068011008482f7b7b2edfcab5fb1b3e9e130f..c7dffdae31877ae194fc6b0a5bf21be203f7dcc4 100644
> --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> @@ -838,10 +838,7 @@ static int analogix_dp_commit(struct analogix_dp_device *dp)
>   	int ret;
>   
>   	/* Keep the panel disabled while we configure video */
> -	if (dp->plat_data->panel) {
> -		if (drm_panel_disable(dp->plat_data->panel))
> -			DRM_ERROR("failed to disable the panel\n");
> -	}
> +	drm_panel_disable(dp->plat_data->panel);
>   
>   	ret = analogix_dp_train_link(dp);
>   	if (ret) {
> @@ -863,13 +860,7 @@ static int analogix_dp_commit(struct analogix_dp_device *dp)
>   	}
>   
>   	/* Safe to enable the panel now */
> -	if (dp->plat_data->panel) {
> -		ret = drm_panel_enable(dp->plat_data->panel);
> -		if (ret) {
> -			DRM_ERROR("failed to enable the panel\n");
> -			return ret;
> -		}
> -	}
> +	drm_panel_enable(dp->plat_data->panel);
>   
>   	/* Check whether panel supports fast training */
>   	ret = analogix_dp_fast_link_train_detection(dp);
> @@ -1136,7 +1127,6 @@ static void analogix_dp_bridge_atomic_pre_enable(struct drm_bridge *bridge,
>   	struct analogix_dp_device *dp = bridge->driver_private;
>   	struct drm_crtc *crtc;
>   	struct drm_crtc_state *old_crtc_state;
> -	int ret;
>   
>   	crtc = analogix_dp_get_new_crtc(dp, old_state);
>   	if (!crtc)
> @@ -1147,11 +1137,7 @@ static void analogix_dp_bridge_atomic_pre_enable(struct drm_bridge *bridge,
>   	if (old_crtc_state && old_crtc_state->self_refresh_active)
>   		return;
>   
> -	if (dp->plat_data->panel) {
> -		ret = drm_panel_prepare(dp->plat_data->panel);
> -		if (ret)
> -			DRM_ERROR("failed to prepare the panel ret = %d\n", ret);
> -	}
> +	drm_panel_prepare(dp->plat_data->panel);
>   }
>   
>   static int analogix_dp_set_bridge(struct analogix_dp_device *dp)
> @@ -1231,17 +1217,11 @@ static void analogix_dp_bridge_atomic_enable(struct drm_bridge *bridge,
>   static void analogix_dp_bridge_disable(struct drm_bridge *bridge)
>   {
>   	struct analogix_dp_device *dp = bridge->driver_private;
> -	int ret;
>   
>   	if (dp->dpms_mode != DRM_MODE_DPMS_ON)
>   		return;
>   
> -	if (dp->plat_data->panel) {
> -		if (drm_panel_disable(dp->plat_data->panel)) {
> -			DRM_ERROR("failed to disable the panel\n");
> -			return;
> -		}
> -	}
> +	drm_panel_disable(dp->plat_data->panel);
>   
>   	disable_irq(dp->irq);
>   
> @@ -1249,11 +1229,7 @@ static void analogix_dp_bridge_disable(struct drm_bridge *bridge)
>   
>   	pm_runtime_put_sync(dp->dev);
>   
> -	if (dp->plat_data->panel) {
> -		ret = drm_panel_unprepare(dp->plat_data->panel);
> -		if (ret)
> -			DRM_ERROR("failed to unprepare the panel ret = %d\n", ret);
> -	}
> +	drm_panel_unprepare(dp->plat_data->panel);
>   
>   	dp->fast_train_enable = false;
>   	dp->psr_supported = false;
> @@ -1678,10 +1654,7 @@ void analogix_dp_unbind(struct analogix_dp_device *dp)
>   	analogix_dp_bridge_disable(dp->bridge);
>   	dp->connector.funcs->destroy(&dp->connector);
>   
> -	if (dp->plat_data->panel) {
> -		if (drm_panel_unprepare(dp->plat_data->panel))
> -			DRM_ERROR("failed to turnoff the panel\n");
> -	}
> +	drm_panel_unprepare(dp->plat_data->panel);
>   
>   	drm_dp_aux_unregister(&dp->aux);
>   
> 

Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>

Re: [PATCH 0/7] drm/panel: make prepare / enable / disable / unprepare return void

[Neil Armstrong]

On 01/04/2025 07:11, Dmitry Baryshkov wrote:
> While it makes sense for panel callbacks to be able to return an error,
> the state-management functions from drm_panel API are usually called
> from atomic callbacks, which can not fails and must return void. Make
> drm_panel_prepare(), drm_panel_enable(), drm_panel_disable() and
> drm_panel_unprepare() follow the same calling convention and return
> void.
> 
> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
> ---
> Dmitry Baryshkov (7):
>        drm/bridge: analogix_dp: drop extra calls to analogix_dp_prepare_panel()
>        drm/bridge: analogix_dp: drop unused argument to analogix_dp_prepare_panel()
>        drm/bridge: analogic_dp: drop panel_is_modeset
>        drm/bridge: analogic_dp: drop panel_lock
>        drm/bridge: analogix_dp: inline analogix_dp_prepare_panel()
>        drm/bridge: analogix_dp: ignore return values of drm_panel_* calls
>        drm/panel: make prepare/enable and disable/unprepare calls return void
> 
>   drivers/gpu/drm/bridge/analogix/analogix_dp_core.c | 107 ++-------------------
>   drivers/gpu/drm/bridge/analogix/analogix_dp_core.h |   3 -
>   drivers/gpu/drm/drm_panel.c                        |  54 ++++-------
>   drivers/gpu/drm/panel/panel-newvision-nv3051d.c    |   9 +-
>   include/drm/drm_panel.h                            |   8 +-
>   5 files changed, 33 insertions(+), 148 deletions(-)
> ---
> base-commit: bfb20a655848a9088e3e9ae24b1dcce1bbf016c2
> change-id: 20250401-panel-return-void-d461c71ebd35
> 
> Best regards,

I think you can respin with the warning fix on patch 1 and then apply

Neil

Re: [PATCH 3/7] drm/bridge: analogic_dp: drop panel_is_modeset

[Dmitry Baryshkov]

On Thu, Apr 17, 2025 at 05:47:00PM +0200, Neil Armstrong wrote:
> On 01/04/2025 07:11, Dmitry Baryshkov wrote:
> > The dp->panel_is_modeset is now a write-only field. Drop it completely.
> > 
> > Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>

Neil, it looks like you wanted to respond with either a comment or an
r-b tag, but none were present in the email...

> > ---
> >   drivers/gpu/drm/bridge/analogix/analogix_dp_core.c | 11 +----------
> >   drivers/gpu/drm/bridge/analogix/analogix_dp_core.h |  1 -
> >   2 files changed, 1 insertion(+), 11 deletions(-)
> > 

-- 
With best wishes
Dmitry

Re: [PATCH 1/7] drm/bridge: analogix_dp: drop extra calls to analogix_dp_prepare_panel()

[Dmitry Baryshkov]

On Mon, Apr 14, 2025 at 10:01:16AM +0800, Damon Ding wrote:
> On 2025/4/14 9:20, Damon Ding wrote:
> > Hi Dmitry,
> > 
> > On 2025/4/1 13:11, Dmitry Baryshkov wrote:
> > > The analogix_dp_prepare_panel() returns immediately if there is no
> > > attached panel. Drop several calls to this function which are performed
> > > when dp->plat_data->panel is NULL.
> > > 
> > > Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
> > > ---
> > >   drivers/gpu/drm/bridge/analogix/analogix_dp_core.c | 22
> > > +---------------------
> > >   1 file changed, 1 insertion(+), 21 deletions(-)
> > > 
> > > diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/
> > > drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> > > index 042154e2d8ccd74ac2dc27fe527e810a50e08a09..ab1cfc340aa95bbf13fe021bd33227b565a5458d
> > > 100644
> > > --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> > > +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> > > @@ -1005,17 +1005,11 @@ static int analogix_dp_get_modes(struct
> > > drm_connector *connector)
> > >   {
> > >       struct analogix_dp_device *dp = to_dp(connector);
> > >       const struct drm_edid *drm_edid;
> > > -    int ret, num_modes = 0;
> > > +    int num_modes = 0;
> > >       if (dp->plat_data->panel) {
> > >           num_modes += drm_panel_get_modes(dp->plat_data->panel,
> > > connector);
> > >       } else {
> > > -        ret = analogix_dp_prepare_panel(dp, true, false);
> > > -        if (ret) {
> > > -            DRM_ERROR("Failed to prepare panel (%d)\n", ret);
> > > -            return 0;
> > > -        }
> > > -
> > >           drm_edid = drm_edid_read_ddc(connector, &dp->aux.ddc);
> > >           drm_edid_connector_update(&dp->connector, drm_edid);
> > > @@ -1024,10 +1018,6 @@ static int analogix_dp_get_modes(struct
> > > drm_connector *connector)
> > >               num_modes += drm_edid_connector_add_modes(&dp->connector);
> > >               drm_edid_free(drm_edid);
> > >           }
> > > -
> > > -        ret = analogix_dp_prepare_panel(dp, false, false);
> > > -        if (ret)
> > > -            DRM_ERROR("Failed to unprepare panel (%d)\n", ret);
> > >       }
> > >       if (dp->plat_data->get_modes)
> > > @@ -1087,19 +1077,9 @@ analogix_dp_detect(struct drm_connector
> > > *connector, bool force)
> > >       if (dp->plat_data->panel)
> > >           return connector_status_connected;
> > > -    ret = analogix_dp_prepare_panel(dp, true, false);
> > > -    if (ret) {
> > > -        DRM_ERROR("Failed to prepare panel (%d)\n", ret);
> > > -        return connector_status_disconnected;
> > > -    }
> > > -
> > >       if (!analogix_dp_detect_hpd(dp))
> > >           status = connector_status_connected;
> > > -    ret = analogix_dp_prepare_panel(dp, false, false);
> > > -    if (ret)
> > > -        DRM_ERROR("Failed to unprepare panel (%d)\n", ret);
> > > -
> > >       return status;
> > >   }
> > > 
> > 
> > With the patch series:
> > https://patchwork.kernel.org/project/linux-rockchip/list/?series=942183
> > 
> > When I verify this patch, there will be a small warning:
> > drivers/gpu/drm/bridge/analogix/analogix_dp_core.c:1075:6: warning:
> > unused variable 'ret' [-Wunused-variable]
> >          int ret;
> >              ^
> > 
> > It should be better to remove the unused 'ret'.

I can't reproduce the warning, so I'd like to push the series once patch
3/7 gets an R-B.

> > 
> > Best regards,
> > Damon
> > 
> > 
> > 
> 
> Tested-by: Damon Ding <damon.ding@rock-chips.com>
> 

-- 
With best wishes
Dmitry

Re: [PATCH 3/7] drm/bridge: analogic_dp: drop panel_is_modeset

[Neil Armstrong]

On 01/04/2025 07:11, Dmitry Baryshkov wrote:
> The dp->panel_is_modeset is now a write-only field. Drop it completely.
> 
> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
> ---
>   drivers/gpu/drm/bridge/analogix/analogix_dp_core.c | 11 +----------
>   drivers/gpu/drm/bridge/analogix/analogix_dp_core.h |  1 -
>   2 files changed, 1 insertion(+), 11 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> index 82dc4b01806f9728dc882b0128171838e81f21b0..704c6169116eb2601d2ad02dc7294455ceff5460 100644
> --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> @@ -964,9 +964,7 @@ static int analogix_dp_disable_psr(struct analogix_dp_device *dp)
>    * is false, the panel will be unprepared.
>    *
>    * The function will disregard the current state
> - * of the panel and either prepare/unprepare the panel based on @prepare. Once
> - * it finishes, it will update dp->panel_is_modeset to reflect the current state
> - * of the panel.
> + * of the panel and either prepare/unprepare the panel based on @prepare.
>    */
>   static int analogix_dp_prepare_panel(struct analogix_dp_device *dp,
>   				     bool prepare)
> @@ -983,12 +981,6 @@ static int analogix_dp_prepare_panel(struct analogix_dp_device *dp,
>   	else
>   		ret = drm_panel_unprepare(dp->plat_data->panel);
>   
> -	if (ret)
> -		goto out;
> -
> -	dp->panel_is_modeset = prepare;
> -
> -out:
>   	mutex_unlock(&dp->panel_lock);
>   	return ret;
>   }
> @@ -1532,7 +1524,6 @@ analogix_dp_probe(struct device *dev, struct analogix_dp_plat_data *plat_data)
>   	dp->dpms_mode = DRM_MODE_DPMS_OFF;
>   
>   	mutex_init(&dp->panel_lock);
> -	dp->panel_is_modeset = false;
>   
>   	/*
>   	 * platform dp driver need containor_of the plat_data to get
> diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
> index 774d11574b095b093ddf2818ad5b84be6605c9bf..b679d5b71d276f458d905c936160f107225bc6c5 100644
> --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
> +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
> @@ -170,7 +170,6 @@ struct analogix_dp_device {
>   	bool			psr_supported;
>   
>   	struct mutex		panel_lock;
> -	bool			panel_is_modeset;
>   
>   	struct analogix_dp_plat_data *plat_data;
>   };
> 

Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>

Re: [PATCH 0/7] drm/panel: make prepare / enable / disable / unprepare return void

[Dmitry Baryshkov]

On Tue, 01 Apr 2025 08:11:32 +0300, Dmitry Baryshkov wrote:
> While it makes sense for panel callbacks to be able to return an error,
> the state-management functions from drm_panel API are usually called
> from atomic callbacks, which can not fails and must return void. Make
> drm_panel_prepare(), drm_panel_enable(), drm_panel_disable() and
> drm_panel_unprepare() follow the same calling convention and return
> void.
> 
> [...]

Applied to drm-misc-next, thanks!

[1/7] drm/bridge: analogix_dp: drop extra calls to analogix_dp_prepare_panel()
      commit: b65cbfe0e1d8bcb74dbeb221d423dd926f326d05
[2/7] drm/bridge: analogix_dp: drop unused argument to analogix_dp_prepare_panel()
      commit: 0ce432e18c932a7fd219b9c2bf1db623fb0f7840
[3/7] drm/bridge: analogic_dp: drop panel_is_modeset
      commit: 4fc72e1fc46b0dca74c1f8c94091e524ad5b9fdb
[4/7] drm/bridge: analogic_dp: drop panel_lock
      commit: 62ca1c3a146c73f8b8a381bf4461a82951defb8b
[5/7] drm/bridge: analogix_dp: inline analogix_dp_prepare_panel()
      commit: d5f34ca5df7c0ae075fdfeba20edd6f81c792554
[6/7] drm/bridge: analogix_dp: ignore return values of drm_panel_* calls
      commit: 58a71d2bf103550f809987e16d8c1949be719040
[7/7] drm/panel: make prepare/enable and disable/unprepare calls return void
      commit: dcbd5dcc956e2331414fd7020b4655df08deeb87

Best regards,
-- 
With best wishes
Dmitry