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Driver and Debugging

This page summarizes Android kernel driver check items and common project modifications, such as init.rc, boot animation, logo, and MIPI display configuration.

Common Driver Items​

Driver topics listed in the original manual include:

  • G-sensor driver.
  • Capacitive touch driver.
  • LCD driver.
  • Key driver.
  • Wi-Fi / BT module driver.
  • Camera driver.
  • VGA driver.
  • HDMI driver.
  • proc file system information query.

proc File System Queries​

Query boot arguments:

cat /proc/cmdline

Query CPU information:

cat /proc/cpuinfo

Query memory information:

cat /proc/meminfo

Query disk partitions:

cat /proc/partitions

Query kernel version:

cat /proc/version

Query network devices:

cat /proc/net/dev

Query kernel boot messages:

cat /proc/kmsg

Modify init.rc​

Permanent method: modify init.rc under system/core/rootdir, then rebuild the system image:

./mk.sh -s

If the change does not take effect, remove the old init.rc under the out directory and rebuild.

Temporary method: init.rc is located in ramdisk, and ramdisk is packed into boot.img. To modify it temporarily, unpack boot.img, edit the ramdisk contents, and repack boot.img.

Modify Boot Animation​

The default Android boot animation can be customized by replacing the boot animation resource and repacking the relevant partition.

Rockchip U-Boot reads logo.bmp and logo_kernel.bmp from the kernel directory:

  • logo.bmp: used as the U-Boot-stage boot logo.
  • logo_kernel.bmp: used as the kernel-stage logo.

To display only one image, remove logo_kernel.bmp. To replace the U-Boot logo, convert the image to BMP, convert it to 8-bit mode, and replace kernel/logo.bmp.

The kernel logo also needs to be converted to BMP and compressed with tools such as GIMP on Linux. The original manual notes that the default Rockchip kernel logo solution has limited resolution and may show color distortion. For a perfect logo, use the standard Linux boot logo solution.

Configure MIPI Display​

The known working MIPI panel configuration file is located at:

kernel/arch/arm/boot/dts/lcd-mipi-7inch-wy070ml.dtsi

When replacing the display panel, modify this file according to the new panel parameters.