Android system-level Tips Collection

Android system-level Tips collection (update at any time)

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1. Qualcomm Snapdragon Dragon series View CPU physique level

The CPU is the voltage at the operating frequency of the CPU. The CPU of the same batch has different physique, the higher the physique, on behalf of the CPU can be at a higher frequency stable operation, and at the same frequency when the power consumption compared to the same batch of poor CPU to control better.

Take the Qualcomm Snapdragon Dragon 801 Millet 4 (OS: Third-party native Android) as an example, in the file under/sys to find the description of the CPU health files.

Path is:/sys/module/clock_krait_8974/parameters/

In this directory in the table_name file, open as text, PVS after the number is the CPU physique, my hands of this PVS value is 5, also means that the representative of the kernel support, can be manually CPU frequency operating voltage global offset 50mV.

2. Check the current charging voltage with the supported maximum voltage, current

In the normal charging current test software, it is often displayed in MV units of the battery voltage, the battery voltage is not equal to the charging voltage at the time of charging. In support of the high-pass Quickcharge protocol models, often take is low current fast charge, such as QC2.0 standard 9v1.2a and 12v1a, at this time only to see the charging current can not determine whether the device is high-pressure fast charge, can not judge whether the charger is really supporting the QC protocol.

Voltage and current information storage location:/SYS/CLASS/POWER_SUPPLY/USB

The Voltage_max supports the maximum charge voltage for the device and voltage_now the current charging voltage for the device.

(for example, 8987487, the charging voltage is currently 8.9V, in the 9V fast charge)

The Current_max supports the maximum charge current for the device and a value of 2000000 is 2 a.

3. Adjust the screen brightness to the lowest supported value

In the vast majority of ROM, the brightness setting of 0 brightness is not the lowest brightness of the screen backlight. By looking at the backlight brightness file under the system catalog, you can see that the brightness level of the system is adjusted to 0 and the backlight degree is 3. At this point, we can directly modify the backlight file method to cross the system limits, the backlight brightness adjustment to a minimum.

Backlight Brightness file directory:/sys/class/leds/lcd-backlight, where the brightness file is the backlight brightness file.

You can use Rootexplorer and other applications, choose to edit the text, the value of the file is changed to 1 is the lowest brightness, save.

(Note: Do not change the value to 0, which causes the LCD backlight to close directly and revert to the system defaults the next time the screen is unlocked)

When you change the brightness file only, you will find that the lock screen will still revert to the lowest brightness of the system once it is unlocked again, just change the value of the max_brightness file in that directory to 1, but it will invalidate the system brightness after the operation (because the highest value has been changed to 1). When low brightness is not required, change the max_brightness to the default value of 255. This can be done automatically with Tasker's shell command, which is described in detail in subsequent posts.

< to Be continued >

Android system-level Tips Collection