tweak kernel-config/config.txt

Signed-off-by: jinqiang zhang <jinqiang@fydeos.io>

Author: jinqiang zhang

chromeos-base/chromeos-bsp-rpi4-fydeos/files/kernel-config/config.txt

@@ -1,3 +1,20 @@
+# Chromium OS for Raspberry Pi
+# Copyright (c) 2021 Fyde Innovations. All rights reserved.
+
+# Use of this source code is governed by a BSD-style license
+# that can be found in the LICENSE file.
+
+# The Raspberry Pi uses a configuration file instead of the
+# BIOS you would expect to find on a conventional PC. The
+# system configuration parameters, which would traditionally
+# be edited and stored using a BIOS, are stored instead in
+# this optional text file. This is read by the GPU before the
+# ARM CPU and Linux are initialised.
+
+# For more info:
+# https://www.raspberrypi.com/documentation/computers/config_txt.html
+
+
 #hdmi_drive=2
 #config_hdmi_boost=7
 disable_overscan=1
@@ -6,11 +23,16 @@ cma_lwm=16
 cma_hwm=32
 gpu_mem=256
 
-# better graphic performance,but need fydeos-force-cursor-compositing in /etc/chrome_dev.conf
+# Display mode
+# Defaulting to "kms" mode for better graphics performance, it
+# requires an optional flag "fydeos-force-cursor-compositing"
+# in /etc/chrome_dev.conf.
+# Should you run into display issues, such as black-screen or
+# GUI graphics not being able to render properly, you can
+# toggle the display mode to "fkms" to enable a compatibility
+# mode, by commenting/uncommenting the corresponding lines.
 dtoverlay=vc4-kms-v3d-pi4
-
-# fit for rpi3/rpi4
-#dtoverlay=vc4-fkms-v3d-rpi4
+#dtoverlay=vc4-fkms-v3d
 
 # for more power
 #force_turbo=1
@@ -27,3 +49,14 @@ arm_64bit=1
 max_framebuffers=2
 kernel=kernel8_a.img
 disable_splash=1
+
+# Supported MIPI Cameras
+# 1. Raspberry Pi Camera V2:
+#dtoverlay=imx219
+# 2. Others:
+#dtoverlay=imx290
+#dtoverlay=imx378
+#dtoverlay=imx477
+#dtoverlay=imx519
+#dtoverlay=ov5647
+#dtoverlay=ov9281