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Adding a system call to AArch64 Linux

May 16th, 2017 by mhyun

No more calls.S. It becomes simpler to add a new syscall.

  1. kernel/include/linux/syscalls.h
    Define the syscall:
    asmlinkage long sys_hong(int k);
  2. implement it somewere.c
  3. kernel/include/uapi/asm-generic/unistd.h
    Link the syscall with a number. Don’t forget update __NR_syscalls accordingly.
    e.g.,
    #define __NR_hong 291
    __SYSCALL(__NR_hong, sys_hong)
    #define __NR_syscalls 292

 

 



Am I using panel self refresh?

March 22nd, 2016 by mhyun

dumpsys SurfaceFlinger | grep Panel
‘DisplayPanel=9’ means I’m using it



Highspeed video of LCD refresh

October 15th, 2015 by mhyun



To reduce blur

October 15th, 2015 by mhyun

backlight scanning & black frame insertion: http://www.tftcentral.co.uk/advanced.htm

 

 



CRT vs LCD

October 15th, 2015 by mhyun

See the refresh.

http://www.blurbusters.com/faq/crt-comparison/

 

 



Monkey from Songtao

September 23rd, 2015 by mhyun

import time

from com.android.monkeyrunner import MonkeyRunner, MonkeyDevice

device = MonkeyRunner.waitForConnection()

# Touch down screen
device.touch(110, 500, MonkeyDevice.DOWN)

# Move from 100, 500 to 300, 500
for j in range(1,100):
for i in range(0, 100):
device.touch(100+j*10, 500+i*10, MonkeyDevice.MOVE)
print “move “, 100 + 20 * i, 500
time.sleep(0.001)

# Move from (300, 500 to 200, 500)
for i in range(0, 100):
device.touch(110+j*10, 500 + 100 * 10 – 10 * i, MonkeyDevice.MOVE)
print “move “, 300, 500 – 10 * i
time.sleep(0.001)

# Remove finger from screen
device.touch(300, 400, MonkeyDevice.UP)



Where is app dir?

October 11th, 2014 by mhyun

/data/data/



Looking into the system.img

April 18th, 2014 by mhyun

out/host/linux-x86/bin/simg2img system.img system.img.raw

mkdir fs_system

sudo  mount -t ext4 -o loop system.img.raw fs_system/



Add a directory to build path

February 3rd, 2014 by mhyun

include the directory you want to build into

/build/core/pathmap.mk

 



Remount /factory

November 25th, 2013 by mhyun

mount -oremount,rw /factory