Why does the system freeze for 2 to 3 seconds when I unplug the USB mouse from the USB hub?

With the popularization of ultra-thin notebooks and PC tablet two-in-one devices, the number of USB external ports on these devices has gradually decreased, and many users are lamenting that the ports are not enough. In order for a notebook to be both slim and connect to a variety of USB peripherals, USB Hub has become an inevitable choice.


USB Hub, also known as USB hub, uses software and hardware algorithms to allocate a certain USB interface (upstream port) of the PC to the USB interface (downstream port) extended by the USB Hub (Figure 1), which can connect a USB flash drive to a notebook at the same time. Mouse, keyboard and other equipment are required.


I saw some users’ feedback on the Internet: his USB Hub interface is connected to the keyboard and mouse at the same time. When the keyboard or mouse is suddenly unplugged, the computer system will be stuck for two to three seconds and sometimes longer. Why? It comes from the identification protocol of the USB Hub. Simply put, USB-Hub uses the enumeration method when adding or deleting devices, while there is only one thread for USB enumeration in the Win system. Therefore, when a device is plugged and unplugged on the Hub, the request of the Hub and its connected USB device will be suspended (the card will be suspended), and the suspension time is related to the performance of the PC and the Hub's main control chip. Generally, the card is about 0.5 seconds or so. If the card is slow for 2-3 seconds, it means you may need to change to a HUB with better master control performance.


STC-USB HUB uses the industry's core RTL5411 chip, real core quality, strong compatibility, high-speed transmission, stable and more reliable. It supports one-to-four port expansion, multi-device use, without interfering with each other, immediately connect the mouse, keyboard, U disk, etc. to enter the working state in time.


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Post time: Nov-16-2021
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