方法1

1）去掉/etc/XF86Config-4中关于扫描频率的参数，让DMPS自动支持高分辨率

Section "Monitor"
        Identifier      "SyncMaster"
        VendorName      "SamSung"
        #HorizSync      28-50
        #VertRefresh    43-75
        Option          "DPMS"
EndSection

2）修改屏幕参数，配置默认色深

Section "Screen"
        Identifier      "Default Screen"
        Device          "Generic Video Card"
        Monitor         "SyncMaster"
        DefaultDepth    24

        SubSection "Display"
                Depth           24
                Modes           "1024x768" "800x600" "640x480"
        EndSubSection
EndSection

方法2:当方法1不管用时，可以试一试

输入下面命令

#gtf 1024 768 85

得到参数

 # 1024x768 @ 85.00 Hz (GTF) hsync: 68.60 kHz; pclk: 94.39 MHz
  Modeline "1024x768_85.00"  94.39  1024 1088 1200 1376  768 769 772 807  -HSync +Vsync

加入到/etc/X11/XF86Config-4中

Section "Monitor"
        Identifier      "SyncMaster"
        VendorName      "SamSung"
         # 1024x768 @ 75.00 Hz (GTF) hsync: 60.15 kHz; pclk: 81.80 MHz
      Modeline "1024x768_85.00"  94.39  1024 1088 1200 1376  768 769 772 807  -HSync +Vsync
        Option          "DPMS"
EndSection