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杏林小草讨论 | 贡献2008年6月9日 (一) 19:04的版本

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如果你的嵌入式系统给出这样的信息:“控制台:正在将显卡切换至80x30模式(Console: switching to colour frame buffer device 80x30)“,那么下面内容将能帮助你。

方案:加入黑名单(The Blacklist Solution)

控制台切换至frame buffer设备,是因为引导期间加载了frame buffer设备驱动。查看哪个frame buffer设备驱动被加载,可以运行命令:

    #lsmod

在我的系统中,我注意到这样的一行:

    gxfb 8832 1

那么,我该如何阻止加载这个驱动呢?Ubuntu提供了一个阻止自动加载驱动的方法。在/etc/modprobe.d中存在着一个黑名单。对我来说,我只要简单地在黑名单文件中加入

    blacklist gxfb

以后,我的系统不再尝试转换到frame buffer控制台。

Increase the number of visible rows and columns in console

Chose preferred console resolution

The default size of the console is 25x80 chars using vga (640x480 pixels) for historical reasons. I order to utilize modern display resolution you will need to override this settings during the operation system boot process. Please note that widescreen format is currently not supported by the kernel console driver. Pick a appropriate value from the matrix below, e.g. 0x31A for 16 bit 1280x1024.

Colours 640x400 640x480 800x600 1024x768 1152x864 1280x1024 1600x1200
--------+--------------------------------------------------------------
4 bits |  ?  ? 0x302  ?  ?  ?  ?
8 bits | 0x300 0x301 0x303 0x305 0x161 0x307 0x31C
15 bits |  ? 0x310 0x313 0x316 0x162 0x319 0x31D
16 bits |  ? 0x311 0x314 0x317 0x163 0x31A 0x31E
24 bits |  ? 0x312 0x315 0x318  ? 0x31B 0x31F
32 bits |  ?  ?  ?  ? 0x164  ?  ?

Edit /boot/grub/menu.lst

Append vga=0x31A in the end of the kernel line. Your root=UUID will look different and do not edit this since it will cause your computer to fail booting. Please be warned. In the kernel line below the option splash is removed since it might cause LCD monitors to entering sleep mode during the boot process when using DVI input. This is not a serious error but a very annoying side-effect from changing the console resolution. This failure might apply on other configurations as well.

title Ubuntu 7.10, kernel 2.6.22-14-generic
root (hd0,0)
kernel /vmlinuz-2.6.22-14-generic root=UUID=98c2b6c5-4f08-4fbf-bd9c-c470b286f614 ro vga=0x31A
initrd /initrd.img-2.6.22-14-generic
quiet
  • Tip, If you would like to test the setting but not make a permanent change as above it's possible to edit grub options during computer booting. When grub is loading press ESC to enter the boot menu, chose to edit the kernel line and append vga=0x31A. Continue to boot linux.

Edit /etc/initramfs-tools/modules

A framebuffer is the device forwarding the text to be outputted on your display. In order to make the operation system aware we changed the size of the console the framebuffer driver needs to be notified. Add two lines containing vesafb and fbcon to /etc/initramfs-tools/modules

sudo bash
echo vesafb >> /etc/initramfs-tools/modules
echo fbcon >> /etc/initramfs-tools/modules

Rebuild the kernel image

This step is necessary to include these two modules in the kernel image being used upon next reboot. This step might also be necessary to perform after a kernel upgrade.

sudo update-initramfs -u

Edit /etc/modprobe.d/blacklist-framebuffer

Framebuffers are sometimes causing problems to wake up the computer from suspend mode and are hence disabled by default. Comment out the line blacklist vesafb to load the module anyway.

# blacklist vesafb

Edit /etc/modules

Although we stopped blacklisting the the vesa framebuffer we force to load it. Append one line with vesafb in /etc/modules

echo vesafb >> /etc/modules

Reboot

Hopefully you should see the boot messages with a smaller font upon the boot process.

Links

This section was assembled using information from different sources.