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Hi, I see your problem. What I wrote is for GRUB2 used by my Ubuntu, so if your Fedora is still using the first version, you should edit /boot/grub/grub.conf (you will need root account for this) and add "acpi_backlight=vendor acpi_osi=linux" (without the quotes, of course) at the end of each line that begins with "kernel". So for example your first Fedora block should become:
title Fedora (2.6.33.5-124.fc13.x86_64) root (hd0,6)
kernel /vmlinuz-2.6.33.5-124.fc13.x86_64 ro root=UUID=236fef23-35fb-4c49-924c-a1be77383ea2 rd_NO_LUKS rd_NO_LVM rd_NO_MD rd_NO_DM LANG=en_US.UTF-8 SYSFONT=latarcyrheb-sun16 KEYTABLE=us rhgb quiet acpi_backlight=vendor acpi_osi=linux
initrd /initramfs-2.6.33.5-124.fc13.x86_64.img
To be sure, first edit just this one block and leave the others as they are. If anything goes wrong, you will be able to choose the older kernel while booting (or you can edit these lines directly during booting - it is explained in the GRUB menu, which comes before your system and where you can choose different kernel). However, I am quite concerned, whether these changes will withstand. Obviously, your grub.conf is automatically generated by a program called Anaconda. I don't use Fedora, so I can't help you with this, but if you find that adding this works for you, you should try to find a way to tell Anaconda to add it to the file automatically every time your system gets new Linux kernel through updates. Otherwise, the changes would get erased after first kernel update.So, to sum up, I have no idea, whether it would work for you on your Fedora, but it fixed my Ubuntu completely. So fingers crossed :-)
David===================================
我就不全部翻译了，直接到重点部分。
打开终端，su成为超级用户，
输入gedit /boot/grub/grub.conf 注意：我是把/boot独立成为一个分区，如果你没有，那么请用locale或者窗口中Ctrl+F，搜索grub.conf这个文件，在kernel那一段最后增加一句：acpi_backlight=vendor acpi_osi=linux
比如我的原本是
title Fedora (2.6.33.5-124.fc13.x86_64) root (hd0,6)
kernel /vmlinuz-2.6.33.5-124.fc13.x86_64 ro root=UUID=236fef23-35fb-4c49-924c-a1be77383ea2 rd_NO_LUKS rd_NO_LVM rd_NO_MD rd_NO_DM LANG=en_US.UTF-8 SYSFONT=latarcyrheb-sun16 KEYTABLE=us rhgb quiet
initrd /initramfs-2.6.33.5-124.fc13.x86_64.img
改动后就是：
title Fedora (2.6.33.5-124.fc13.x86_64) root (hd0,6)
kernel /vmlinuz-2.6.33.5-124.fc13.x86_64 ro root=UUID=236fef23-35fb-4c49-924c-a1be77383ea2 rd_NO_LUKS rd_NO_LVM rd_NO_MD rd_NO_DM LANG=en_US.UTF-8 SYSFONT=latarcyrheb-sun16 KEYTABLE=us rhgb quiet acpi_backlight=vendor acpi_osi=linux
initrd /initramfs-2.6.33.5-124.fc13.x86_64.img
重新启动以后，就变为正常了。
非常感谢David。