From 997695bf8cc4468c70cdf0dea414652ae9065ec8 Mon Sep 17 00:00:00 2001
From: Jeff <125375211+dragged9698@users.noreply.github.com>
Date: Sun, 30 Aug 2026 00:52:15 -0400
Subject: [PATCH] media: i2c: ov13858: apply 180-degree sensor flip on Surface
 Pro 9

The Surface Pro 9 rear OV13858 (OVTID858) is mounted upside-down.
SSDB reports degree=0, and PipeWire does not rotate buffers from V4L2
Rotation metadata, so the image stays inverted even after ipu-bridge
reports Rotation=180.

Do not advertise V4L2 HFLIP/VFLIP: libcamera remaps Bayer order from
those controls and the image washes out. After the mode table is
programmed, set the FORMAT2 horizontal bits the ov5693 uses on this
tablet plus the ov13b10 FORMAT1 vertical bits (4 and 5). The ov5693
FORMAT1 bits are a no-op on this die.

Report rotation=0 when the hardware flip is applied so clients that
do honor metadata do not double-rotate.

Tested on Surface Pro 9 (CachyOS 6.19.8-1-cachyos-surface) with
PipeWire and libcamera. Front ov5693 is unchanged.

Link: https://github.com/linux-surface/linux-surface/issues/1892
Link: https://github.com/linux-surface/kernel/pull/170
Patchset: cameras
Signed-off-by: Jeff <125375211+dragged9698@users.noreply.github.com>
Co-authored-by: Cursor <cursoragent@cursor.com>
---
 drivers/media/i2c/ov13858.c | 71 +++++++++++++++++++++++++++++++++++++
 1 file changed, 71 insertions(+)

diff --git a/drivers/media/i2c/ov13858.c b/drivers/media/i2c/ov13858.c
index 85cd0c98af031..5b109ccd2a4fc 100644
--- a/drivers/media/i2c/ov13858.c
+++ b/drivers/media/i2c/ov13858.c
@@ -4,6 +4,7 @@
 #include <linux/acpi.h>
 #include <linux/delay.h>
 #include <linux/clk.h>
+#include <linux/dmi.h>
 #include <linux/i2c.h>
 #include <linux/module.h>
 #include <linux/pm_runtime.h>
@@ -82,6 +83,21 @@
 #define OV13858_TEST_PATTERN_ENABLE	BIT(7)
 #define OV13858_TEST_PATTERN_MASK	0xfc
 
+/*
+ * Surface Pro 9 rear module is mounted 180 degrees. PipeWire ignores
+ * V4L2 Rotation, so flip in the sensor. Do not expose HFLIP/VFLIP
+ * (libcamera remaps Bayer). Horizontal bits match ov5693 on this
+ * module; vertical bits are the ov13b10 FORMAT1 pair (ov5693 FORMAT1
+ * bits are a no-op on this die).
+ */
+#define OV13858_REG_FORMAT1			0x3820
+#define OV13858_REG_FORMAT2			0x3821
+#define OV13858_FORMAT1_FLIP_VERT		(BIT(4) | BIT(5))
+#define OV13858_FORMAT2_FLIP_HORZ_ISP		BIT(2)
+#define OV13858_FORMAT2_FLIP_HORZ_SENSOR	BIT(1)
+
+static const struct dmi_system_id surface_pro_9_dmi[];
+
 /* Number of frames to skip */
 #define OV13858_NUM_OF_SKIP_FRAMES	2
 
@@ -1331,6 +1347,33 @@ static int ov13858_enable_test_pattern(struct ov13858 *ov13858, u32 pattern)
 				 OV13858_REG_VALUE_08BIT, val);
 }
 
+static int ov13858_or_reg(struct ov13858 *ov13858, u16 reg, u8 bits)
+{
+	u32 val;
+	int ret;
+
+	ret = ov13858_read_reg(ov13858, reg, OV13858_REG_VALUE_08BIT, &val);
+	if (ret)
+		return ret;
+
+	return ov13858_write_reg(ov13858, reg, OV13858_REG_VALUE_08BIT,
+				 val | bits);
+}
+
+static int ov13858_apply_rot180(struct ov13858 *ov13858)
+{
+	int ret;
+
+	ret = ov13858_or_reg(ov13858, OV13858_REG_FORMAT1,
+			     OV13858_FORMAT1_FLIP_VERT);
+	if (ret)
+		return ret;
+
+	return ov13858_or_reg(ov13858, OV13858_REG_FORMAT2,
+			      OV13858_FORMAT2_FLIP_HORZ_ISP |
+			      OV13858_FORMAT2_FLIP_HORZ_SENSOR);
+}
+
 static int ov13858_set_ctrl(struct v4l2_ctrl *ctrl)
 {
 	struct ov13858 *ov13858 = container_of(ctrl->handler,
@@ -1567,6 +1610,16 @@ static int ov13858_start_streaming(struct ov13858 *ov13858)
 	if (ret)
 		return ret;
 
+	/* After the mode table so 0x3820/0x3821 are in a known state. */
+	if (dmi_check_system(surface_pro_9_dmi)) {
+		ret = ov13858_apply_rot180(ov13858);
+		if (ret) {
+			dev_err(ov13858->dev,
+				"failed to apply Surface Pro 9 180-degree flip\n");
+			return ret;
+		}
+	}
+
 	return ov13858_write_reg(ov13858, OV13858_REG_MODE_SELECT,
 				 OV13858_REG_VALUE_08BIT,
 				 OV13858_MODE_STREAMING);
@@ -1675,6 +1728,16 @@ static const struct v4l2_subdev_internal_ops ov13858_internal_ops = {
 	.open = ov13858_open,
 };
 
+static const struct dmi_system_id surface_pro_9_dmi[] = {
+	{
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "Microsoft Corporation"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "Surface Pro 9"),
+		},
+	},
+	{ }
+};
+
 /* Initialize control handlers */
 static int ov13858_init_controls(struct ov13858 *ov13858)
 {
@@ -1760,6 +1823,14 @@ static int ov13858_init_controls(struct ov13858 *ov13858)
 	if (ret)
 		goto error;
 
+	/*
+	 * Pixel flip is applied at stream-on. Report rotation=0 so clients
+	 * that honor metadata (and ipu-bridge quirks that set 180) do not
+	 * also rotate the already-corrected image.
+	 */
+	if (dmi_check_system(surface_pro_9_dmi))
+		props.rotation = 0;
+
 	ret = v4l2_ctrl_new_fwnode_properties(ctrl_hdlr, &ov13858_ctrl_ops,
 					      &props);
 	if (ret)