Update NanoKVM-USB Docs

docs/hardware/en/kvm/NanoKVM_USB/faq.md

@@ -17,6 +17,12 @@ keywords: NanoKVM-USB, Lichee, PiKVM, RISCV, tool
 
 + Some Linux distributions come with `brltty`, a Braille display tool that occupies the `/dev/ttyUSB0` serial port, causing the webpage to be unable to detect it. If you are not using `brltty`, it is recommended to uninstall it with `sudo apt remove brltty`.
 
+### Poor Video Quality
+
++ First, check if you're using a USB 2.0 cable/HOST interface. When the resolution is high, USB 2.0 may not provide sufficient bandwidth, which can lower the video quality. It is recommended to use a USB 3.0 cable.
++ At 2K resolution, the video quality may decrease due to the chip's encoding capability. Please switch to 1080P.
++ If the target device is connected to a Windows host, go to System Settings > Display Settings > Advanced Display Settings, and change to 1080P60 in the "List all modes" section. Also, check if the "Desktop Resolution" and "Active Signal Resolution" are consistent.
+
 ### Unable to Open NanoKVM-USB Corresponding Serial Device After Opening Web Page
 
 + This may be due to other programs occupying the serial port. Please ensure it is not in use before trying again.

docs/hardware/zh/kvm/NanoKVM_USB/faq.md

@@ -26,6 +26,12 @@ keywords: NanoKVM-USB, Lichee, PiKVM, RISCV, tool
 
 ## 视频问题
 
+### 视频画质差
+
++ 首先检查是否使用了 USB2.0 的线缆/HOST接口，当分辨率较大时 USB2.0 不足以提供充足的传输带宽，会被动降低画质，建议选用 USB3.0的线缆
++ 2K分辨率下首先于芯片编码能力，画质会下降，请切换为1080P使用
++ 如果 Target 连接的是 Windws主机，请前往系统设置-显示设置-高级显示设置-列出所有模式中更改为 1080P60，并检查`桌面分辨率`和`活动信号分辨率是否一致`
+
 ### DP-HDMI转接器
 
 + 部分无源DP转HDMI转换器内部电路仅做电平转换，对NanoKVM-USB兼容性较差，表现为视频信号从无到有（比如从睡眠唤醒时）NanoKVM-USB仍显示然黑屏，需要手动拔插HDMI。