Points related to android wifi current

I recently want to change the firmware of wifi in the tablet, so I am always dealing with the current after the wifi connection. Now Let's sum up. After a Wi-Fi connection, when the screen is disabled on the tablet, the wifi may be disconnected according to the sleep policy configured in Settings. When the sleep policy is set to "always connect" in Settings, wifi does not disconnect after the flat screen is disabled. In this way, apps may communicate with each other in the background, causing the flat panel to sleep, the current is relatively high. When the sleep policy configured in Settings is "disconnected", wifi will disconnect after the flat screen is disabled for 17 minutes, which is determined in 17 minutes, in 15th minutes, the wifi service will determine whether the current "emergency call mode" is available. If yes, the connection will be closed immediately. If not, the connection will be disconnected after 2 minutes. However, you still need to check whether an app is holding a Wi-Fi wake lock. If an app holds this lock, the connection cannot be closed. This will also lead to high current. Within 10 minutes between screen disconnection and disconnection, if it is normal, when the cpu Of the tablet is sleeping, the average current should be only 1ma higher than that of the wifi chip (this value is the sleep current of the wifi chip); however, in this case, the average current measured will be higher than 1ma, this requires us to analyze the cause. Some points related to current may not be completely recorded here. If you find them again later, supplement them. 1. wifi firmware is the most closely related to the high current during wifi sleep, and we cannot know the logic in it, so we can only request the support from the manufacturer. 2. The dtim value affects the beacon packets received by wifi firmware. It indicates that the wifi chip will wake up to receive beacon packets at several beacon intervals, which is generally set to 3. If the dtim value is set to 1, the wifi chip will wake up frequently, resulting in a higher current than expected. If the dtim value is set to 5, it may cause serious packet loss after wifi sleep. For example, if you ping the tablet, the ping may fail. 3. the SDIO pin configuration error of the SDIO pin wifi chip will also lead to high current after sleep. Therefore, you need to check whether SDIO is correctly configured. When sleep, whether the PIN is pulled up or down incorrectly. (I don't quite understand this one. I need to learn about it later.) 4.gsf gsf is a service framework of google, and its behavior is different in the case of wifi connection and no connection. If the Wi-Fi connection is used, it will wake up the cpu every other time and try to connect to the google server, which will also lead to a high average current. 5. If other apps hold the rtc_wakeup timer, the app will also wake up the cpu to perform operations, resulting in a high average current.