Kernel Modding - Part 1
PLEASE DONT ASK HOW OR WHY ANY PART IS DONE. I WILL EXPLAIN ALL THAT I KNOW. BUT SOME PART OF THIS HAS BEEN DONE BY TRIAL AND ERROR METHOD, WHEREAS SOME PART MAYBE OUT OF MY SCOPE OF KNOWLEDGE.
Removing The Sound Click Bug During Calls
We all know that this is the most basic bug found out in the Kernel of Samsung. The clicking sound we get during calls. Many of you may complain that this bug is solved in the newer ROM's, but remember we are building from the original Samsung Source, which is modified in the newer kernel's. We dont have those modifications so here it goes, the Sound Click Bug.
We to find out this bug you need to check the dmesg when you are in a call.
It shows you that there is some sound routing done during the call. So you know that this is something related to the sound driver.
Now the sound driver for Galaxy 3 is the wm8994 driver, which is present at Kernel/sound/soc/codecs/
So the changes to be made are in the file wm8994.c
In the function static int wm8994_resume(struct platform_device *pdev)
Originally the code was
Code:
if (wm8994_power == 0) {
audio_power(1); /* Board Specific function */
wm8994_power = 1;
}
wm8994_set_bias_level(codec, SND_SOC_BIAS_STANDBY);
wm8994_enable_path(codec, wm8994_curr_path);
After editing the code is
Code:
if (wm8994_power == 0) {
audio_power(1); /* Board Specific function */
wm8994_power = 1;
wm8994_set_bias_level(codec, SND_SOC_BIAS_STANDBY);
wm8994_enable_path(codec, wm8994_curr_path);
}
1% Battery MOD
The battery driver for galaxy 3 is found at Kernel/drivers/power/
The file to be added is s5p6442_battery.c
The Samsung battery driver originally divides battery in the following Steps:
100,90,80,70,60,50,40,30,20,15,5,3,1
If you look at the source code, you should be able to find that out easily.
We need to make it return each value in between also so that we get the 1% MOD that is required.
So now, the original code was
Code:
if (bat_vol > batt_full)
{
int temp = (batt_max - batt_full);
if (bat_vol > (batt_full + temp) ||
s3c_bat_info.bat_info.batt_is_full)
bat_level = 100;
else
bat_level = 90;
#ifdef __CHECK_CHG_CURRENT__
if (s3c_bat_info.bat_info.charging_enabled) {
check_chg_current(bat_ps);
if (!s3c_bat_info.bat_info.batt_is_full)
bat_level = 90;
}
#endif /* __CHECK_CHG_CURRENT__ */
dev_dbg(dev, "%s: (full)level = %d\n", __func__, bat_level );
}
else if (batt_full >= bat_vol && bat_vol > batt_almost)
{
int temp = (batt_full - batt_almost) / 2;
if (bat_vol > (batt_almost + 86))
bat_level = 80;
else
bat_level = 70;
dev_dbg(dev, "%s: (almost)level = %d\n", __func__, bat_level);
}
else if (batt_almost >= bat_vol && bat_vol > batt_high)
{
int temp = (batt_almost - batt_high) / 2;
if (bat_vol > (batt_high + 62))
bat_level = 60;
else
bat_level = 50;
dev_dbg(dev, "%s: (high)level = %d\n", __func__, bat_level );
}
else if (batt_high >= bat_vol && bat_vol > batt_medium)
{
int temp = (batt_high - batt_medium) / 2;
if (bat_vol > (batt_medium + 26))
bat_level = 40;
else
bat_level = 30;
dev_dbg(dev, "%s: (med)level = %d\n", __func__, bat_level);
}
else if (batt_medium >= bat_vol && bat_vol > batt_low)
{
int temp = (batt_medium - batt_low) / 2;
if (bat_vol > (batt_low + 50))
bat_level = 20;
else
bat_level = 15;
dev_dbg(dev, "%s: (low)level = %d\n", __func__, bat_level);
}
else if (batt_low >= bat_vol && bat_vol > batt_critical)
{
bat_level = 5;
dev_dbg(dev, "%s: (cri)level = %d, vol = %d\n", __func__,
bat_level, bat_vol);
}
else if (batt_critical >= bat_vol && bat_vol > batt_min)
{
bat_level = 3;
dev_info(dev, "%s: (min)level = %d, vol = %d\n", __func__,
bat_level, bat_vol);
}
else if (batt_min >= bat_vol && bat_vol > batt_off)
{
bat_level = 1;
dev_info(dev, "%s: (off)level = %d, vol = %d\n", __func__,
bat_level, bat_vol);
}
else if (batt_off >= bat_vol)
{
bat_level = 0;
dev_info(dev, "%s: (off)level = %d, vol = %d", __func__,
bat_level, bat_vol);
}
We need to edit it to make
Code:
if (bat_vol > batt_full)
{
int temp = (batt_max - batt_full);
if (bat_vol > (batt_full + temp) ||
s3c_bat_info.bat_info.batt_is_full)
bat_level = 100;
else
{
bat_level = 90 + (((bat_vol - batt_full) *10) / temp);
}
#ifdef __CHECK_CHG_CURRENT__
if (s3c_bat_info.bat_info.charging_enabled) {
check_chg_current(bat_ps);
if (!s3c_bat_info.bat_info.batt_is_full)
bat_level = 90;
}
#endif /* __CHECK_CHG_CURRENT__ */
dev_dbg(dev, "%s: (full)level = %d\n", __func__, bat_level );
}
else if (batt_full >= bat_vol && bat_vol > batt_almost)
{
int temp = (batt_full - batt_almost) / 2;
bat_level = 70 + (((bat_vol - batt_almost) *10) / temp);
dev_dbg(dev, "%s: (almost)level = %d\n", __func__, bat_level);
}
else if (batt_almost >= bat_vol && bat_vol > batt_high)
{
int temp = (batt_almost - batt_high) / 2;
bat_level = 50 + (((bat_vol - batt_high) *10) / temp);
dev_dbg(dev, "%s: (high)level = %d\n", __func__, bat_level );
}
else if (batt_high >= bat_vol && bat_vol > batt_medium)
{
int temp = (batt_high - batt_medium) / 2;
bat_level = 30 + (((bat_vol - batt_medium) *10) / temp);
dev_dbg(dev, "%s: (med)level = %d\n", __func__, bat_level);
}
else if (batt_medium >= bat_vol && bat_vol > batt_low)
{
int temp = (batt_medium - batt_low) / 2;
bat_level = 15 + ((( bat_vol - batt_low) *5) / temp);
dev_dbg(dev, "%s: (low)level = %d\n", __func__, bat_level);
}
else if (batt_low >= bat_vol && bat_vol > batt_critical)
{
bat_level = 5;
dev_dbg(dev, "%s: (cri)level = %d, vol = %d\n", __func__,
bat_level, bat_vol);
}
else if (batt_critical >= bat_vol && bat_vol > batt_min)
{
bat_level = 3;
dev_info(dev, "%s: (min)level = %d, vol = %d\n", __func__,
bat_level, bat_vol);
}
else if (batt_min >= bat_vol && bat_vol > batt_off)
{
bat_level = 1;
dev_info(dev, "%s: (off)level = %d, vol = %d\n", __func__,
bat_level, bat_vol);
}
else if (batt_off >= bat_vol)
{
bat_level = 0;
dev_info(dev, "%s: (off)level = %d, vol = %d", __func__,
bat_level, bat_vol);
}
and also we need to change the Total ADC count
Originally
Code:
#define ADC_TOTAL_COUNT 20
Change it to
Code:
#define ADC_TOTAL_COUNT 100
Voodoo Sound Driver
The Sound Driver for Galaxy 3 is the wm8994 Wolfson Microelectronics Codec.
The WM8994 is a highly integrated ultra-low power hi-fi CODEC designed for smartphones and other portable devices rich in multimedia features.
Features
- Hi-Fi 24-bit 4-channel DAC and 2-channel ADC
- 100dB SNR during stereo DAC playback (‘A’ weighted)
- Smart MIC interface
- Power, clocking and data input for up to four digital MICs
- High performance analogue MIC interface
- MIC activity monitor & interrupt allows processor to sleep
- 1W stereo / 2W mono class D/AB speaker driver
- Capless class W headphone drivers
- Integrated charge pump
- 6mW total power for DAC playback to headphones
- 4 line outputs (single-ended or differential)
- BTL earpiece driver
- Digital audio interfaces for multi-processor architecture
- Asynchronous stereo duplex sample rate conversion
- Powerful mixing and digital loopback functions
- ReTune™ Mobile 5-band, 6-channel parametric EQ
- Programmable dynamic range controller
- Dual FLL provides all necessary clocks
- Self-clocking modes allows processor to sleep
- All standard sample rates from 8kHz to 96kHz
- Active noise reduction circuits
- DC offset correction removes pops and clicks
- Ground loop noise cancellation
- Integrated LDO regulators
- 72-ball W-CSP package (4.511mm x 4.023mm x 0.7mm)
The Voodoo Driver is developed by
supercurio.
The changes to be made for the voodoo driver are at sound/soc/codec/
The Changes are as the following Commit. (Please ignore the /Kernel/scripts part....I forgot to do a make clean -i before commiting 
)
RootADB and BusyBox
Android Debug Bridge (adb) is a versatile command line tool that lets you communicate with an emulator instance or connected Android-powered device. It is a client-server program that includes three components:
- A client, which runs on your development machine. You can invoke a client from a shell by issuing an adb command. Other Android tools such as the ADT plugin and DDMS also create adb clients.
- A server, which runs as a background process on your development machine. The server manages communication between the client and the adb daemon running on an emulator or device.
- A daemon, which runs as a background process on each emulator or device instance.
You can find the adb tool in <sdk>/platform-tools/.
RootADB gives you root access while performing adb functions.
BusyBox combines tiny versions of many common UNIX utilities into a single small executable. It provides replacements for most of the utilities you usually find in GNU fileutils, shellutils, etc. The utilities in BusyBox generally have fewer options than their full-featured GNU cousins; however, the options that are included provide the expected functionality and behave very much like their GNU counterparts. BusyBox provides a fairly complete environment for any small or embedded system.
BusyBox has been written with size-optimization and limited resources in mind. It is also extremely modular so you can easily include or exclude commands (or features) at compile time. This makes it easy to customize your embedded systems. To create a working system, just add some device nodes in /dev, a few configuration files in /etc, and a Linux kernel.
The Changes to be made for these are in the initramfs.
These can be found in this Commit.
