对 Linux 来说相当新，所以如果我错过了一些显而易见的东西，请原谅我。我试图在 Ubuntu 18.04 盒子上使用 2 个显示器，每个显示器连接到不同的 VGA 适配器。第一个适配器是板载的，它是 Matrox G200，第二个适配器是 Ati firPpro V3900。
视频子系统似乎没有将第二台显示器识别为显示器。
系统可以看到两个适配器并都附有驱动程序。
sudo lshw -c display
*-display
description: VGA compatible controller
product: Turks GL [FirePro V3900]
vendor: Advanced Micro Devices, Inc. [AMD/ATI]
physical id: 0
bus info: pci@0000:04:00.0
logical name: /dev/fb1
version: 00
width: 64 bits
clock: 33MHz
capabilities: pm pciexpress msi vga_controller bus_master cap_list rom fb
configuration: depth=32 driver=radeon latency=0 mode=2560x1440 visual=truecolor xres=2560 yres=1440
resources: iomemory:3ff0-3fef irq:53 memory:3fff0000000-3ffffffffff memory:d9fc0000-d9fdffff ioport:ec00(size=256) memory:d9000000-d901ffff
*-display
description: VGA compatible controller
product: G200eR2
vendor: Matrox Electronics Systems Ltd.
physical id: 0
bus info: pci@0000:0c:00.0
version: 00
width: 32 bits
clock: 33MHz
capabilities: pm vga_controller bus_master cap_list rom
configuration: driver=mgag200 latency=64 maxlatency=32 mingnt=16
resources: irq:19 memory:d4000000-d4ffffff memory:dbffc000-dbffffff memory:db000000-db7fffff memory:c0000-dffff
no@r720:~$ lspci | grep 'VGA'
04:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Turks GL [FirePro V3900]
0c:00.0 VGA compatible controller: Matrox Electronics Systems Ltd. G200eR2
并且两者都可供 xserver 使用
no@r720:~$ xrandr --listproviders
Providers: number : 2
Provider 0: id: 0x7f cap: 0x0 crtcs: 1 outputs: 1 associated providers: 0 name:modesetting
Provider 1: id: 0x47 cap: 0x6, Sink Output, Source Offload crtcs: 6 outputs: 2 associated providers: 0 name:TURKS @ pci:0000:04:00.0
himi@r720:~$
但是，我无法在辅助适配器上获得任何显示，并且桌面显示配置仅显示连接到 matrox 适配器的显示。
我尝试使用 gtm3 的 Gnome 桌面，也尝试安装 KDE Plasma 并将桌面管理器切换到 SDDM，但问题依旧，只有一个显示器可通过桌面控制面板进行配置。
顺便提一下，我还试过老款的 Nvidia quadro p400 显卡，也出现了同样的情况。当我尝试使用 Nvidia 专有驱动程序时，系统在启动到一半时卡住了，反复尝试启动某项功能（屏幕闪烁速度太快，看不清）。
我下载了专有的 Ati 驱动程序，但安装程序会出错，说 x 子系统是不受支持的版本（太新），而回滚这些旧卡的 xwindow 子系统似乎不是明智之举。
关于如何进行有什么想法吗？
谢谢！
更新
更新 我看到了一些类似的问题，安装和 \ 或重新配置显示管理器可以正常工作。我尝试了 sudo dpkg-reconfigure sddm。没有运气。然后我尝试安装 lightdm 并重新启动。同样没有运气。我的 /var/log/gpu-manager.log 文件也没有显示太多内容。
log_file: /var/log/gpu-manager.log
last_boot_file: /var/lib/ubuntu-drivers-common/last_gfx_boot
new_boot_file: /var/lib/ubuntu-drivers-common/last_gfx_boot
can't access /run/u-d-c-nvidia-was-loaded file
can't access /opt/amdgpu-pro/bin/amdgpu-pro-px
Looking for nvidia modules in /lib/modules/5.0.0-37-generic/updates/dkms
Looking for amdgpu modules in /lib/modules/5.0.0-37-generic/updates/dkms
Is nvidia loaded? no
Was nvidia unloaded? no
Is nvidia blacklisted? no
Is intel loaded? no
Is radeon loaded? yes
Is radeon blacklisted? no
Is amdgpu loaded? no
Is amdgpu blacklisted? no
Is amdgpu versioned? no
Is amdgpu pro stack? no
Is nouveau loaded? no
Is nouveau blacklisted? yes
Is nvidia kernel module available? no
Is amdgpu kernel module available? no
Vendor/Device Id: 1002:674a
BusID "PCI:4@0:0:0"
Is boot vga? no
Vendor/Device Id: 102b:534
BusID "PCI:12@0:0:0"
Is boot vga? yes
Skipping "/dev/dri/card1", driven by "radeon"
Skipping "/dev/dri/card0", driven by "mgag200"
Found "/dev/dri/card1", driven by "radeon"
output 0:
card1-DVI-I-1
Number of connected outputs for /dev/dri/card1: 1
Skipping "/dev/dri/card1", driven by "radeon"
Skipping "/dev/dri/card0", driven by "mgag200"
Skipping "/dev/dri/card1", driven by "radeon"
Skipping "/dev/dri/card0", driven by "mgag200"
Does it require offloading? no
last cards number = 2
Has amd? yes
Has intel? no
Has nvidia? no
How many cards? 2
Has the system changed? No
Unsupported discrete card vendor: 1002
Nothing to do