5.4 設定 X11

5.4.1 在開始之前

在開始設定 X11 之前，要先瞭解所要裝的機器資料為何：

• 螢幕規格

• 顯示卡的晶片規格

• 顯示卡的記憶體容量

X11 會依螢幕規格來決定解析度以及更新頻率。 這些規格通常可從螢幕所附的文件或廠商網站上取得。 最重要的是要知道水平、垂直更新頻率為何。

而顯示卡晶片則決定 X11 要用哪一種驅動程式模組。 大多數的晶片都可以自動偵測，但最好還是要知道是何種晶片， 以免萬一自動偵測失敗。

Video memory on the graphic adapter determines the resolution and color depth which the system can run at. This is important to know so the user knows the limitations of the system.

5.4.2 設定 X11

Xorg 自 7.3 版起不再需任何設定檔，只要打下列即可：

% startx

若這指令不行或預設設定無法使用，那麼就需要手動設定 X11。 設定 X11 需要幾個步驟，首先是以系統管理者帳號來建立初始設定檔：

# Xorg -configure

這會在 /root 目錄內產生 xorg.conf.new 設定檔(無論是用 su(1) 或直接登入為 root，都會改變 root 預設的 $HOME 環境變數)。 X11 程式接著會偵測系統的顯示卡相關硬體，並將偵測到硬體訊息寫入設定檔， 以便載入正確的驅動程式。

下一步是測試現有的設定檔，以便確認 Xorg 可以與顯示卡、螢幕相關硬體正確運作：

# Xorg -config xorg.conf.new

若看得到一堆黑灰夾雜的網格畫面，以及 X 形的滑鼠游標， 那麼設定檔就是成功的。 要退出測試，只要同時按下 Ctrl+Alt+Backspace 即可。

Next, tune the xorg.conf.new configuration file to taste. Open the file in a text editor such as emacs(1) or ee(1). First, add the frequencies for the target system's monitor. These are usually expressed as a horizontal and vertical synchronization rate. These values are added to the xorg.conf.new file under the "Monitor" section:

Section "Monitor"
        Identifier   "Monitor0"
        VendorName   "Monitor Vendor"
        ModelName    "Monitor Model"
        HorizSync    30-107
        VertRefresh  48-120
EndSection

The HorizSync and VertRefresh keywords may be missing in the configuration file. If they are, they need to be added, with the correct horizontal synchronization rate placed after the HorizSync keyword and the vertical synchronization rate after the VertRefresh keyword. In the example above the target monitor's rates were entered.

X allows DPMS (Energy Star) features to be used with capable monitors. The xset(1) program controls the time-outs and can force standby, suspend, or off modes. If you wish to enable DPMS features for your monitor, you must add the following line to the monitor section:

        Option       "DPMS"

While the xorg.conf.new configuration file is still open in an editor, select the default resolution and color depth desired. This is defined in the "Screen" section:

Section "Screen"
        Identifier "Screen0"
        Device     "Card0"
        Monitor    "Monitor0"
        DefaultDepth 24
        SubSection "Display"
                Viewport  0 0
                Depth     24
                Modes     "1024x768"
        EndSubSection
EndSection

The DefaultDepth keyword describes the color depth to run at by default. This can be overridden with the -depth command line switch to Xorg(1). The Modes keyword describes the resolution to run at for the given color depth. Note that only VESA standard modes are supported as defined by the target system's graphics hardware. In the example above, the default color depth is twenty-four bits per pixel. At this color depth, the accepted resolution is 1024 by 768 pixels.

Finally, write the configuration file and test it using the test mode given above.

If all is well, the configuration file needs to be installed in a common location where Xorg(1) can find it. This is typically /etc/X11/xorg.conf or /usr/local/etc/X11/xorg.conf.

# cp xorg.conf.new /etc/X11/xorg.conf

The X11 configuration process is now complete. Xorg 目前可透過 startx(1) 來啟動之。 The X11 server may also be started with the use of xdm(1).

5.4.3 進階設定專欄

Section "Screen"
Identifier "Screen0"
Device     "Card0"
Monitor    "Monitor0"
DefaultDepth 24
SubSection "Display"
    Viewport  0 0
    Depth     24
    Modes     "1680x1050"
EndSubSection
EndSection

(II) MGA(0): Supported additional Video Mode:
(II) MGA(0): clock: 146.2 MHz   Image Size:  433 x 271 mm
(II) MGA(0): h_active: 1680  h_sync: 1784  h_sync_end 1960 h_blank_end 2240 h_border: 0
(II) MGA(0): v_active: 1050  v_sync: 1053  v_sync_end 1059 v_blanking: 1089 v_border: 0
(II) MGA(0): Ranges: V min: 48  V max: 85 Hz, H min: 30  H max: 94 kHz, PixClock max 170 MHz

 ModeLine <name> <clock> <4 horiz. timings> <4 vert. timings>

Section "Monitor"
Identifier      "Monitor1"
VendorName      "Bigname"
ModelName       "BestModel" 
ModeLine        "1680x1050" 146.2 1680 1784 1960 2240 1050 1053 1059 1089 
Option          "DPMS"
EndSection