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Target Debugging and Verification

A successful build does not prove that the new configuration entered the firmware or that the target driver works. Verify the source, build output, packaged image, and runtime state separately.

Source and Configuration​

cd <ANDROID_TOP>
git status --short
git diff -- longan/bsp longan/device longan/kernel device vendor hardware

cd longan
cat .buildconfig
CONFIG_FILE=$(find out -type f -path '*/kernel/build/.config' | head -1)
grep -n 'CONFIG_<TARGET_SYMBOL>' "$CONFIG_FILE"

DTB and Modules​

find out -type f -name '*.dtb' -print
find out -type f -name '*.ko' -print | grep -i '<module-keyword>'

dtc -I dtb -O dts -o /tmp/final.dts <dtb-path>
grep -n -A20 -B5 '<node-or-compatible>' /tmp/final.dts

Firmware Identity​

ls -lh --time-style=long-iso <firmware-path>
sha256sum <firmware-path>

adb shell getprop ro.build.fingerprint
adb shell getprop ro.build.date.utc
adb shell uname -a
adb shell cat /proc/version

Kernel Logs​

adb root
adb shell dmesg | grep -i '<driver-or-device>'
adb shell dmesg -w

Look for probe failures, deferred probe, clock/reset/pinctrl/regulator errors, IRQ failures, timeouts, and I/O errors.

Android Logs and Services​

adb logcat -b all
adb shell dumpsys
adb shell lshal

Device Nodes and Driver Binding​

adb shell ls -l /dev
adb shell ls -l /sys/class
adb shell ls -l /sys/bus/platform/drivers
adb shell 'find /sys/bus/platform/drivers -maxdepth 2 -type l 2>/dev/null | head -100'

Runtime Device Tree​

adb shell 'find /proc/device-tree -maxdepth 5 -type f 2>/dev/null | head -100'
adb shell 'tr -d "\000" < /proc/device-tree/<node-path>/status'

Modules and Kernel Configuration​

adb shell cat /proc/modules
adb shell lsmod
adb shell zcat /proc/config.gz 2>/dev/null | grep 'CONFIG_<TARGET_SYMBOL>'

Use the generated Longan .config when /proc/config.gz is unavailable.

hardware power and pins
    ↓
Device Tree and pinctrl
    ↓
menuconfig and CONFIG symbol
    ↓
driver included in the build
    ↓
DTB/module included in firmware
    ↓
kernel probe log
    ↓
HAL and Android service
    ↓
application behavior

Change one variable at a time and preserve the patch, build log, and boot log for every test.