我正在尝试通过 HDMI 向我的联想笔记本电脑添加第二台显示器。但是，它根本没有检测到第二个。
这是来自的输出xrandr：
xrandr: Failed to get size of gamma for output default
Screen 0: minimum 1920 x 1080, current 1920 x 1080, maximum 1920 x 1080
default connected primary 1920x1080+0+0 0mm x 0mm
1920x1080 77.00*
这是来自的输出inxi -Gxx：
Graphics: Card: Advanced Micro Devices [AMD/ATI] Picasso
bus-ID: 03:00.0 chip-ID: 1002:15d8
Display Server: x11 (X.Org 1.20.1 )
drivers: fbdev,ati (unloaded: modesetting,vesa,radeon)
Resolution: 1920x1080@77.00hz
OpenGL: renderer: llvmpipe (LLVM 7.0, 128 bits)
version: 3.3 Mesa 18.2.8 (compat-v: 3.1) Direct …