FAILED: patch "[PATCH] drm/panel: ebbg-ft8719: Set prepare_prev_first" failed to apply to 6.6-stable tree

FAILED: patch "[PATCH] drm/panel: ebbg-ft8719: Set prepare_prev_first" failed to apply to 6.6-stable tree

[Sasha Levin]

The patch below does not apply to the 6.6-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y
git checkout FETCH_HEAD
git cherry-pick -x 4eeeac9d7c3600a6cae75b2a7bc9c5b67530923c
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '20261107053009-failed-6.6-4eeeac9d7c36@kernel.org' --subject-prefix 'PATCH 6.6.y' 'HEAD^..'

Thanks,
Sasha

------------------ original commit in Linus's tree ------------------

From 4eeeac9d7c3600a6cae75b2a7bc9c5b67530923c Mon Sep 17 00:00:00 2001
From: Casey Connolly <casey.connolly@linaro.org>
Date: Tue, 8 Sep 2026 14:45:02 +0200
Subject: [PATCH] drm/panel: ebbg-ft8719: Set prepare_prev_first

This corrects the host initialisation sequence so that we can send
DSI/DCS commands in prepare().

Cc: stable@vger.kernel.org
Fixes: b00de0e237da ("drm/panel: introduce ebbg,ft8719 panel")
Signed-off-by: Casey Connolly <casey.connolly@linaro.org>
Tested-by: Marco Mattiolo <marco.mattiolo@hotmail.it>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Signed-off-by: David Heidelberg <david@ixit.cz>
Reviewed-by: Linus Walleij <linusw@kernel.org>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patch.msgid.link/20260908-ebbg-ft8719-fixups-v2-1-5454ae1f5581@ixit.cz
---
 drivers/gpu/drm/panel/panel-ebbg-ft8719.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/panel/panel-ebbg-ft8719.c b/drivers/gpu/drm/panel/panel-ebbg-ft8719.c
index fb9f9f42be4f2..1ab09c50a6306 100644
--- a/drivers/gpu/drm/panel/panel-ebbg-ft8719.c
+++ b/drivers/gpu/drm/panel/panel-ebbg-ft8719.c
@@ -198,6 +198,8 @@ static int ebbg_ft8719_probe(struct mipi_dsi_device *dsi)
 	dsi->mode_flags = MIPI_DSI_MODE_VIDEO | MIPI_DSI_MODE_VIDEO_BURST |
 			  MIPI_DSI_CLOCK_NON_CONTINUOUS;
 
+	ctx->panel.prepare_prev_first = true;
+
 	ret = drm_panel_of_backlight(&ctx->panel);
 	if (ret)
 		return dev_err_probe(dev, ret, "Failed to get backlight\n");
-- 
2.53.0

[PATCH 6.6.y 1/3] drm/panel: Add new helpers for refcounted panel allocatons

[Sasha Levin]

From: Anusha Srivatsa <asrivats@redhat.com>

[ Upstream commit ed9c594d495deb676825489032cee0a03ce29bf9 ]

Introduce reference counted allocations for panels to avoid
use-after-free. The patch adds the macro devm_drm_bridge_alloc()
to allocate a new refcounted panel. Followed the documentation for
drmm_encoder_alloc() and devm_drm_dev_alloc and other similar
implementations for this purpose.

Reviewed-by: Maxime Ripard <mripard@kernel.org>
Signed-off-by: Anusha Srivatsa <asrivats@redhat.com>
Link: https://lore.kernel.org/r/20250331-b4-panel-refcounting-v4-1-dad50c60c6c9@redhat.com
Signed-off-by: Maxime Ripard <mripard@kernel.org>
Stable-dep-of: 4eeeac9d7c36 ("drm/panel: ebbg-ft8719: Set prepare_prev_first")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/gpu/drm/drm_panel.c | 25 +++++++++++++++++++++++++
 include/drm/drm_panel.h     | 22 ++++++++++++++++++++++
 2 files changed, 47 insertions(+)

diff --git a/drivers/gpu/drm/drm_panel.c b/drivers/gpu/drm/drm_panel.c
index 98df4788d096f..ea1f42cee44dc 100644
--- a/drivers/gpu/drm/drm_panel.c
+++ b/drivers/gpu/drm/drm_panel.c
@@ -336,6 +336,31 @@ struct drm_panel *of_drm_find_panel(const struct device_node *np)
 }
 EXPORT_SYMBOL(of_drm_find_panel);
 
+void *__devm_drm_panel_alloc(struct device *dev, size_t size, size_t offset,
+			     const struct drm_panel_funcs *funcs,
+			     int connector_type)
+{
+	void *container;
+	struct drm_panel *panel;
+
+	if (!funcs) {
+		dev_warn(dev, "Missing funcs pointer\n");
+		return ERR_PTR(-EINVAL);
+	}
+
+	container = devm_kzalloc(dev, size, GFP_KERNEL);
+	if (!container)
+		return ERR_PTR(-ENOMEM);
+
+	panel = container + offset;
+	panel->funcs = funcs;
+
+	drm_panel_init(panel, dev, funcs, connector_type);
+
+	return container;
+}
+EXPORT_SYMBOL(__devm_drm_panel_alloc);
+
 /**
  * of_drm_get_panel_orientation - look up the orientation of the panel through
  * the "rotation" binding from a device tree node
diff --git a/include/drm/drm_panel.h b/include/drm/drm_panel.h
index 10015891b056f..daaa259ef898f 100644
--- a/include/drm/drm_panel.h
+++ b/include/drm/drm_panel.h
@@ -269,6 +269,28 @@ struct drm_panel {
 	bool enabled;
 };
 
+void *__devm_drm_panel_alloc(struct device *dev, size_t size, size_t offset,
+			     const struct drm_panel_funcs *funcs,
+			     int connector_type);
+
+/**
+ * devm_drm_panel_alloc - Allocate and initialize a refcounted panel.
+ *
+ * @dev: struct device of the panel device
+ * @type: the type of the struct which contains struct &drm_panel
+ * @member: the name of the &drm_panel within @type
+ * @funcs: callbacks for this panel
+ * @connector_type: the connector type (DRM_MODE_CONNECTOR_*) corresponding to
+ * the panel interface
+ *
+ * Returns:
+ * Pointer to container structure embedding the panel, ERR_PTR on failure.
+ */
+#define devm_drm_panel_alloc(dev, type, member, funcs, connector_type) \
+	((type *)__devm_drm_panel_alloc(dev, sizeof(type), \
+					offsetof(type, member), funcs, \
+					connector_type))
+
 void drm_panel_init(struct drm_panel *panel, struct device *dev,
 		    const struct drm_panel_funcs *funcs,
 		    int connector_type);
-- 
2.53.0

[PATCH 6.6.y 2/3] panel/ebbg-ft8719: Use refcounted allocation in place of devm_kzalloc()

[Sasha Levin]

From: Anusha Srivatsa <asrivats@redhat.com>

[ Upstream commit b30a15a4e7e54b676d6c395e71daf5f286997731 ]

Move to using the new API devm_drm_panel_alloc() to allocate the
panel.

Signed-off-by: Anusha Srivatsa <asrivats@redhat.com>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://lore.kernel.org/r/20250401-b4-drm-panel-mass-driver-convert-v1-9-cdd7615e1f93@redhat.com
Signed-off-by: Maxime Ripard <mripard@kernel.org>
Stable-dep-of: 4eeeac9d7c36 ("drm/panel: ebbg-ft8719: Set prepare_prev_first")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/gpu/drm/panel/panel-ebbg-ft8719.c | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/panel/panel-ebbg-ft8719.c b/drivers/gpu/drm/panel/panel-ebbg-ft8719.c
index e85d63a176d04..74b56ee42fa49 100644
--- a/drivers/gpu/drm/panel/panel-ebbg-ft8719.c
+++ b/drivers/gpu/drm/panel/panel-ebbg-ft8719.c
@@ -198,9 +198,11 @@ static int ebbg_ft8719_probe(struct mipi_dsi_device *dsi)
 	struct ebbg_ft8719 *ctx;
 	int i, ret;
 
-	ctx = devm_kzalloc(dev, sizeof(*ctx), GFP_KERNEL);
-	if (!ctx)
-		return -ENOMEM;
+	ctx = devm_drm_panel_alloc(dev, struct ebbg_ft8719, panel,
+				   &ebbg_ft8719_panel_funcs,
+				   DRM_MODE_CONNECTOR_DSI);
+	if (IS_ERR(ctx))
+		return PTR_ERR(ctx);
 
 	for (i = 0; i < ARRAY_SIZE(ctx->supplies); i++)
 		ctx->supplies[i].supply = regulator_names[i];
@@ -231,9 +233,6 @@ static int ebbg_ft8719_probe(struct mipi_dsi_device *dsi)
 	dsi->mode_flags = MIPI_DSI_MODE_VIDEO | MIPI_DSI_MODE_VIDEO_BURST |
 			  MIPI_DSI_CLOCK_NON_CONTINUOUS;
 
-	drm_panel_init(&ctx->panel, dev, &ebbg_ft8719_panel_funcs,
-		       DRM_MODE_CONNECTOR_DSI);
-
 	ret = drm_panel_of_backlight(&ctx->panel);
 	if (ret)
 		return dev_err_probe(dev, ret, "Failed to get backlight\n");
-- 
2.53.0

[PATCH 6.6.y 3/3] drm/panel: ebbg-ft8719: Set prepare_prev_first

[Sasha Levin]

From: Casey Connolly <casey.connolly@linaro.org>

[ Upstream commit 4eeeac9d7c3600a6cae75b2a7bc9c5b67530923c ]

This corrects the host initialisation sequence so that we can send
DSI/DCS commands in prepare().

Cc: stable@vger.kernel.org
Fixes: b00de0e237da ("drm/panel: introduce ebbg,ft8719 panel")
Signed-off-by: Casey Connolly <casey.connolly@linaro.org>
Tested-by: Marco Mattiolo <marco.mattiolo@hotmail.it>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Signed-off-by: David Heidelberg <david@ixit.cz>
Reviewed-by: Linus Walleij <linusw@kernel.org>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patch.msgid.link/20260908-ebbg-ft8719-fixups-v2-1-5454ae1f5581@ixit.cz
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/gpu/drm/panel/panel-ebbg-ft8719.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/panel/panel-ebbg-ft8719.c b/drivers/gpu/drm/panel/panel-ebbg-ft8719.c
index 74b56ee42fa49..c97825177693f 100644
--- a/drivers/gpu/drm/panel/panel-ebbg-ft8719.c
+++ b/drivers/gpu/drm/panel/panel-ebbg-ft8719.c
@@ -233,6 +233,8 @@ static int ebbg_ft8719_probe(struct mipi_dsi_device *dsi)
 	dsi->mode_flags = MIPI_DSI_MODE_VIDEO | MIPI_DSI_MODE_VIDEO_BURST |
 			  MIPI_DSI_CLOCK_NON_CONTINUOUS;
 
+	ctx->panel.prepare_prev_first = true;
+
 	ret = drm_panel_of_backlight(&ctx->panel);
 	if (ret)
 		return dev_err_probe(dev, ret, "Failed to get backlight\n");
-- 
2.53.0