服务器评测这个问题的发现是在我换了Ubuntu 8.04并升级内核后发现的，之前的内核是2.6.24-16,没有出现问题。
但是更新了一次，内核升级到2.6.24-20就出现问题了。当时以为是grub的问题，因为menu.lst里还保留了splash选项，
而我已经删除了usplash，所以修改menu.lst去掉generic后的quiet和splash选项。然后就看具体的启动步骤：发现：
[ 7.180660] libata version 3.00 loaded.
[ 7.182664] ata_piix 0000:00:1f.2: version 2.12
[ 7.182670] ata_piix 0000:00:1f.2: MAP [ P0 P2 IDE IDE ]
[ 7.336546] ACPI: PCI Interrupt 0000:00:1f.2[B] -> GSI 17 (level, low) -> IRQ 18
[ 7.336667] PCI: Setting latency timer of device 0000:00:1f.2 to 64
[ 7.336793] scsi0 : ata_piix
[ 7.336895] scsi1 : ata_piix
[ 7.337655] ata1: SATA max UDMA/133 cmd 0×1f0 ctl 0×3f6 bmdma 0xbfa0 irq 14
[ 7.337706] ata2: PATA max UDMA/100 cmd 0×170 ctl 0×376 bmdma 0xbfa8 irq 15
后，系统无响应了30s，当时我按了caps lock也没响应。30s后系统才识别并初始化好我的fujitsu的硬盘和nec的刻录光驱。
找到出问题的原因后，我google了出现的问题，发现很多用ubuntu8.04的都出现这个问题
而且貌似2.6.24-18及其以上版本内核才会出现，不同的机子出现的问题不一样，有scsi的，也有ahci的等。
解决方法：
提供了4种，我没用修改bios的方法。而是用的最后一种，而且我们出问题的地方不一样-我的是scsi，所以用下面的方法搞定：
sudo vim /etc/initramfs-tools/modules
添加：
scsi
ata_piix
保存退出
sudo update-initramfs -k all -u
sudo reboot
没有任何问题了，然后测试了sda的分区和nec的光驱，没问题
####下面我把原文贴上来，供大家参考
[SOLVED] ahci adding 30-seconds to startup?
hopefully someone has a solution for this little issue of mine…
boot-up hangs for about 30-seconds at the following text during startup:
Jul 11 09:18:07 thinkpad kernel: [ 14.174626] ahci 0000:00:1f.2: nr_ports (4) and implemented port map (0×1) don’t match, using nr_ports
Jul 11 09:18:07 thinkpad kernel: [ 14.174708] ahci 0000:00:1f.2: forcing PORTS_IMPL to 0xf
i’ve searched google and other threads, but nothing seems to work short of adding “acpi=off” to my grub kernel line and that is NOT an option since i’m on a laptop.
thanks, in-advance.
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EDIT 1:
okay, to add a little more info… i found through self-discovery ahci issues are occasionally related to bios issues, so i went into bios and changed my sata choice from “ahci” to “compatibility.” now, the wait doesn’t occur as above; rather, it waits
here:
Jul 13 14:39:41 thinkpad kernel: [ 24.320919] ata1.00: configured for UDMA/100
Jul 13 14:39:41 thinkpad kernel: [ 24.640481] ata2.00: ATAPI: HL-DT-STCD-RW/DVD DRIVE GCC-4244N, 1.02, max UDMA/33
hopefully, this extra info will allow SOMEBODY to give me a suggestion or two…
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EDIT 2:
so, i’ve updated the bios to the latest version, changed the sata choice back to “ahci” and now the lag is only ~10-seconds; still irritating, but not nearly as bad as before. the hang still occurs at the “ata2.00: ATAPI: HL-DT-STCD-RW/DVD DRIVE
GCC-4244N, 1.02, max UDMA/33″ line. still awaiting any ideas!
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EDIT 3:
okay, you can almost disregard the above… sometimes boot still hangs at the ahci nr_ports thing, still for 30-seconds, and other times it hangs as the ATAPI DVD thing, for about 10-seconds. what gives!? please, someone…ANYONE… suggestions?
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EDIT 4:
okay, this should be my final edit, as i SEEM to have solved the issue. for anyone else having this issue, the following steps MIGHT work for you too…
1. edit /etc/initramfs-tools/modules and write-in a specific order of modules to load at boot:
sudo nano /etc/initramfs-tools/modules
and add
ahci
ata_piix
2. update initramfs:
sudo update-initramfs -k all -u
3. reboot and see…
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希望对出现类似问题的人有帮助
