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On Fri, Jan 21, 2011 at 12:53 PM, <meino.cramer@×××.de> wrote: |
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<SNIP> |
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> Hi Dale, |
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> |
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> *IDEA* |
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> |
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> Mark said, that the kernel alone is defining, whether to talk AHCI or |
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> IDE to the harddisk and there is not a single result here from my |
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> experiments, that makes me believe, that Mark is wrong with that... |
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> |
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Mark also said 'Don't trust Mark' so be careful about anything Mark |
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says here! ;-)) |
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> Why not to switch back to IDE in the BIOS, which again makes it |
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> possible to boot from USB/DVD since it is used far before the |
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> kernel image takes over. |
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> |
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If Mike's assessment is correct then the reason not to do that is that |
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once the kernel boots it wouldn't know that the hardware is AHCI |
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capable and you almost certainly would get lower performance. |
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> When the kernel boots, the chips are "brainwashed" and after that they are |
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> "thinking AHCI" instead of IDE.... |
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> |
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I think it's more what Mike suggested. The chips have a control bit in |
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them that changes the way they work. If the bit is set to IDE then |
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then chips never tell the kernel that they can do SATA so the kernel |
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never tries. |
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I booted into BIOS here. I have an option called "SATA Configuration" |
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which is set to Enhanced. It offers Disabled and Compatible also. |
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BIOS then gives me another choice "Configure SATA as" which I have set |
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to IDE. It offers RAID and AHCI also. |
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This allows the system to boot CDs and still allows the kernel to run |
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SATA at full speed. |
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- Mark |
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