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FAILED: patch "[PATCH] drm/sysfb: simpledrm: Improve panel-size validation" failed to apply to 6.6-stable tree

PATCH New [email protected] 2 participants 2 messages Sep 9 – Sep 12

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Stable branch DRM drivers DRM misc DRM driver for firmware framebuffers
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[email protected]

author maintainer
#0 lore raw

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 <[email protected]>.

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 3a75a0761914d01c7362adf1f906cc1d1762c189
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2026090930-septum-throttle-3dae@gregkh' --subject-prefix 'PATCH 6.6.y' 'HEAD^..'

Possible dependencies:

thanks,

greg k-h

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

From 3a75a0761914d01c7362adf1f906cc1d1762c189 Mon Sep 17 00:00:00 2001
From: Thomas Zimmermann <[email protected]>
Date: Thu, 25 Jun 2026 11:39:34 +0200
Subject: [PATCH] drm/sysfb: simpledrm: Improve panel-size validation

Validate the panel size from the device-tree node against the limitations of struct drm_display_mode. The type only stores sizes in 16-bit fields. Fail transparently on errors; do not warn.

v3:
- move comments to a more prominent place (Thierry) v2:
- only use initialized values in debugging output (Sashiko)

Signed-off-by Thomas Zimmermann <[email protected]>
Reviewed-by Thierry Reding <[email protected]>
Reviewed-by Maxime Ripard <[email protected]>
Reviewed-by Javier Martinez Canillas <[email protected]>
Fixes 2a6d731a8f16 ("drm/simpledrm: Allow physical width and height configuration via panel node")
Cc Rayyan Ansari <[email protected]>
Cc <[email protected]> # v6.4+
Link https://patch.msgid.link/[email protected] open here
drivers/gpu/drm/sysfb/simpledrm.c +46 -3
index 15dcafa9d524..6bbe779ec870 100644
@@ -193,6 +193,39 @@ simplefb_get_memory_of(struct drm_device *dev, struct device_node *of_node)
 	return res;
 }
 
+static int __simplefb_get_panel_size_mm_of(struct drm_device *dev,
+					   struct device_node *of_panel_node,
+					   const char *name)
+{
+	int ret;
+	u32 value;
+
+	ret = of_property_read_u32(of_panel_node, name, &value);
+	if (ret) {
+		drm_dbg(dev, "simplefb: cannot parse panel %s: error %d\n",
+			name, ret);
+		return ret;
+	} else if (value > U16_MAX) {
+		drm_dbg(dev, "simplefb: panel %s of %u exceeds maximum value\n",
+			name, value);
+		return -EINVAL;
+	}
+
+	return value;
+}
+
+static int simplefb_get_panel_width_mm_of(struct drm_device *dev,
+					  struct device_node *of_panel_node)
+{
+	return __simplefb_get_panel_size_mm_of(dev, of_panel_node, "width-mm");
+}
+
+static int simplefb_get_panel_height_mm_of(struct drm_device *dev,
+					   struct device_node *of_panel_node)
+{
+	return __simplefb_get_panel_size_mm_of(dev, of_panel_node, "height-mm");
+}
+
 /*
  * Simple Framebuffer device
  */

@@ -594,7 +627,7 @@ static struct simpledrm_device *simpledrm_device_create(struct drm_driver *drv,
 	struct drm_sysfb_device *sysfb;
 	struct drm_device *dev;
 	int width, height, stride;
-	int width_mm = 0, height_mm = 0;
+	u16 width_mm = 0, height_mm = 0;
 	struct device_node *panel_node;
 	const struct drm_format_info *format;
 	struct resource *res, *mem = NULL;

@@ -658,8 +691,18 @@ static struct simpledrm_device *simpledrm_device_create(struct drm_driver *drv,
 			return ERR_CAST(mem);
 		panel_node = of_parse_phandle(of_node, "panel", 0);
 		if (panel_node) {
-			simplefb_read_u32_of(dev, panel_node, "width-mm", &width_mm);
-			simplefb_read_u32_of(dev, panel_node, "height-mm", &height_mm);
+			/*
+			 * Ignore errors from parsing the physical panel
+			 * size. Using the pre-initialized sizes of 0 will
+			 * make drm_sysfb_mode() calculate a default physical
+			 * size based on a resolution of 96 dpi.
+			 */
+			ret = simplefb_get_panel_width_mm_of(dev, panel_node);
+			if (ret > 0)
+				width_mm = ret;
+			ret = simplefb_get_panel_height_mm_of(dev, panel_node);
+			if (ret > 0)
+				height_mm = ret;
 			of_node_put(panel_node);
 		}
 	} else {
maintainer
#1 lore raw

PATCH 1/1 drm/sysfb: simpledrm: Improve panel-size validation

From: Thomas Zimmermann <[email protected]>

[ Upstream commit 3a75a0761914d01c7362adf1f906cc1d1762c189 ]

Validate the panel size from the device-tree node against the limitations of struct drm_display_mode. The type only stores sizes in 16-bit fields. Fail transparently on errors; do not warn.

v3:
- move comments to a more prominent place (Thierry) v2:
- only use initialized values in debugging output (Sashiko)

Signed-off-by Thomas Zimmermann <[email protected]>
Reviewed-by Thierry Reding <[email protected]>
Reviewed-by Maxime Ripard <[email protected]>
Reviewed-by Javier Martinez Canillas <[email protected]>
Fixes 2a6d731a8f16 ("drm/simpledrm: Allow physical width and height configuration via panel node")
Cc Rayyan Ansari <[email protected]>
Cc <[email protected]> # v6.4+
Link https://patch.msgid.link/[email protected] open here
Signed-off-by Sasha Levin <[email protected]>
---
 drivers/gpu/drm/tiny/simpledrm.c | 49 ++++++++++++++++++++++++++++++--
 1 file changed, 46 insertions(+), 3 deletions(-)
drivers/gpu/drm/tiny/simpledrm.c +46 -3
index 30676b1073034..2abe80eec793b 100644
@@ -210,6 +210,39 @@ simplefb_get_memory_of(struct drm_device *dev, struct device_node *of_node)
 	return res;
 }
 
+static int __simplefb_get_panel_size_mm_of(struct drm_device *dev,
+					   struct device_node *of_panel_node,
+					   const char *name)
+{
+	int ret;
+	u32 value;
+
+	ret = of_property_read_u32(of_panel_node, name, &value);
+	if (ret) {
+		drm_dbg(dev, "simplefb: cannot parse panel %s: error %d\n",
+			name, ret);
+		return ret;
+	} else if (value > U16_MAX) {
+		drm_dbg(dev, "simplefb: panel %s of %u exceeds maximum value\n",
+			name, value);
+		return -EINVAL;
+	}
+
+	return value;
+}
+
+static int simplefb_get_panel_width_mm_of(struct drm_device *dev,
+					  struct device_node *of_panel_node)
+{
+	return __simplefb_get_panel_size_mm_of(dev, of_panel_node, "width-mm");
+}
+
+static int simplefb_get_panel_height_mm_of(struct drm_device *dev,
+					   struct device_node *of_panel_node)
+{
+	return __simplefb_get_panel_size_mm_of(dev, of_panel_node, "height-mm");
+}
+
 /*
  * Simple Framebuffer device
  */

@@ -625,7 +658,7 @@ static struct simpledrm_device *simpledrm_device_create(struct drm_driver *drv,
 	struct simpledrm_device *sdev;
 	struct drm_device *dev;
 	int width, height, stride;
-	int width_mm = 0, height_mm = 0;
+	u16 width_mm = 0, height_mm = 0;
 	struct device_node *panel_node;
 	const struct drm_format_info *format;
 	struct resource *res, *mem = NULL;

@@ -685,8 +718,18 @@ static struct simpledrm_device *simpledrm_device_create(struct drm_driver *drv,
 			return ERR_CAST(mem);
 		panel_node = of_parse_phandle(of_node, "panel", 0);
 		if (panel_node) {
-			simplefb_read_u32_of(dev, panel_node, "width-mm", &width_mm);
-			simplefb_read_u32_of(dev, panel_node, "height-mm", &height_mm);
+			/*
+			 * Ignore errors from parsing the physical panel
+			 * size. Using the pre-initialized sizes of 0 will
+			 * make drm_sysfb_mode() calculate a default physical
+			 * size based on a resolution of 96 dpi.
+			 */
+			ret = simplefb_get_panel_width_mm_of(dev, panel_node);
+			if (ret > 0)
+				width_mm = ret;
+			ret = simplefb_get_panel_height_mm_of(dev, panel_node);
+			if (ret > 0)
+				height_mm = ret;
 			of_node_put(panel_node);
 		}
 	} else {
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