1 files changed, 41 insertions, 0 deletions
diff --git a/target/linux/bcm27xx/patches-5.15/950-0699-ARM-dts-Permanently-disable-hdmi1-and-ddc1-on-CM4S.patch b/target/linux/bcm27xx/patches-5.15/950-0699-ARM-dts-Permanently-disable-hdmi1-and-ddc1-on-CM4S.patch
new file mode 100644
index 0000000000..04b5081cf6
--- /dev/null
+++ b/target/linux/bcm27xx/patches-5.15/950-0699-ARM-dts-Permanently-disable-hdmi1-and-ddc1-on-CM4S.patch
@@ -0,0 +1,41 @@
+From 27dd29f219300bf3d4e5c26d5986ab6c73faa1e7 Mon Sep 17 00:00:00 2001
+From: Phil Elwell <phil@raspberrypi.com>
+Date: Wed, 2 Feb 2022 17:47:54 +0000
+Subject: [PATCH] ARM: dts: Permanently disable hdmi1 and ddc1 on CM4S
+
+CM4S has no HDMI1 output, so it is advisable to disable the controller
+and its I2C interface in software. This is ordinarily done by setting
+their status properties to "disabled", but the vc4-kms-v3d(-pi4)
+overlay enables both HDMIs and DDCs as part of the transfer of control
+from the VPU.
+
+Knobble the CM4S dts in such a way that the overlay applies
+successfully but the hdmi1 and ddc1 nodes remain disabled by changing
+the compatible string to something unrecognised.
+
+See: https://github.com/raspberrypi/linux/issues/4857
+
+Signed-off-by: Phil Elwell <phil@raspberrypi.com>
+---
+ arch/arm/boot/dts/bcm2711-rpi-cm4s.dts | 10 ++++++++++
+ 1 file changed, 10 insertions(+)
+
+--- a/arch/arm/boot/dts/bcm2711-rpi-cm4s.dts
++++ b/arch/arm/boot/dts/bcm2711-rpi-cm4s.dts
+@@ -367,6 +367,16 @@
+ 	};
+ };
+ 
++/* Permanently disable HDMI1 */
++&hdmi1 {
++	compatible = "disabled";
++};
++
++/* Permanently disable DDC1 */
++&ddc1 {
++	compatible = "disabled";
++};
++
+ &leds {
+ 	act_led: led-act {
+ 		label = "led0";