103 lines
4.4 KiB
Text
103 lines
4.4 KiB
Text
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Information related to EDD3.0 and ELILO
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---------------------------------------
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Last updated: 02/02/14
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As of elilo-3.0, the filesystem/device naming scheme takes advantage
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of the EDD3.0 support present in the underlying EFI/BIOS firmware layers.
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The EDD3.0 support is supposedly turned on by default in all version of the
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EFI firmware on IA-64 (and possibly IA-32).
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Support can be enabled or disabled dynamically using an EFI environment
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variable called "EDD30". The GUID of the variable is as follows:
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#define EDD30_GUID \
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{0x964e5b21, 0x6459, 0x11d2, { 0x8e, 0x39, 0x00, 0xa0, 0xc9, 0x69, 0x72, 0x3b}}
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This is a boolean variable. When true, support is enabled.
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You can check if support is enabled by typing:
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Shell> edd30
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Usage edd30 [On | Off]
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Used to support OS Loader debug
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EDD30 DevicePath Mode is On
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at this EFI shell prompt. You can enable support by forcing the variable
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to TRUE. This can be accomplished by typing:
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Shell> edd30 on
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EDD30 DevicePath Mode is On
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Alternatively an EFI application can use RT->SetVariable() to set the
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value of the EDD30 variable.
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If the variable was set to false, then to take advantage of EDD3.0
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support after switching the variablle to TRUE, the system MUST be
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rebooted as EDD affects the core of EFI naming scheme.
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Elilo will check if the variable is defined and valid. If it is set
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to true, then the device name schemes that rely on it will work properly.
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That's the case for the 'simple' scheme. If the variable is not set to true
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or does not exist, elilo will use a generic builtin scheme with names
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such as dev001, dev002 and so on. The "EDD30" variable is like a system
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variable therefore it is expected not to be overloaded by users for others
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purposes. Elilo is fully functional even when EDD30 is off.
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By default, if EDD30 is off, elilo will try and set the variable to TRUE.
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However, some controllers do not support EDD30 and forcing the variable
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may cause problems. Therefore as of elilo-3.2, there is an option to
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avoid forcing the variable. In the config file, you can use 'noedd30' option
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and on the command line, you can use the -E option.
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When the variable is forced back to TRUE, th effect will only be seen after
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a reboot. Shall you decide not to reboot immediately, elilo
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will system still operate using the generic naming scheme.
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When EDD3.0 is enabled the output of the EFI shell 'map' command looks similar
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to this:
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Device mapping table
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fs0 : Acpi(PNP0A03,2)/Pci(0|0)/Scsi(Pun0,Lun0)/HD(Part1,Sig00000000)
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fs1 : Acpi(PNP0A03,2)/Pci(0|0)/Scsi(Pun6,Lun0)/HD(Part1,Sig00000000)
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fs2 : Acpi(PNP0A03,0)/Pci(3|1)/Ata(Secondary,Master)/CDROM(Entry1)
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blk0 : Acpi(PNP0A03,0)/Pci(3|1)/Ata(Primary,Master)
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blk1 : Acpi(PNP0A03,2)/Pci(0|0)/Scsi(Pun0,Lun0)
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blk2 : Acpi(PNP0A03,2)/Pci(0|0)/Scsi(Pun0,Lun0)/HD(Part1,Sig00000000)
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blk3 : Acpi(PNP0A03,2)/Pci(0|0)/Scsi(Pun0,Lun0)/HD(Part2,Sig00000000)
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blk4 : Acpi(PNP0A03,2)/Pci(0|0)/Scsi(Pun0,Lun0)/HD(Part3,Sig00000000)
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blk5 : Acpi(PNP0A03,2)/Pci(0|0)/Scsi(Pun6,Lun0)
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blk6 : Acpi(PNP0A03,2)/Pci(0|0)/Scsi(Pun6,Lun0)/HD(Part1,Sig00000000)
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blk7 : Acpi(PNP0A03,2)/Pci(0|0)/Scsi(Pun6,Lun0)/HD(Part2,Sig00000000)
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blk8 : Acpi(PNP0A03,2)/Pci(0|0)/Scsi(Pun6,Lun0)/HD(Part3,Sig00000000)
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blk9 : Acpi(PNP0A03,2)/Pci(0|0)/Scsi(Pun6,Lun0)/HD(Part3,Sig00000000)/HD(Part1,Sig00000200)
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blkA : Acpi(PNP0A03,0)/Pci(3|1)/Ata(Secondary,Master)
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blkB : Acpi(PNP0A03,0)/Pci(3|1)/Ata(Secondary,Master)/CDROM(Entry1)
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Shell>
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The same system with EDD3.0 disabled will look like this:
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Device mapping table
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fs0 : VenHw(Unknown Device:80)/HD(Part1,Sig00000000)
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fs1 : VenHw(Unknown Device:81)/HD(Part1,Sig00000000)
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fs2 : VenHw(Unknown Device:FF)/CDROM(Entry1)
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blk0 : VenHw(Unknown Device:00)
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blk1 : VenHw(Unknown Device:80)
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blk2 : VenHw(Unknown Device:80)/HD(Part1,Sig00000000)
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blk3 : VenHw(Unknown Device:80)/HD(Part2,Sig00000000)
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blk4 : VenHw(Unknown Device:80)/HD(Part3,Sig00000000)
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blk5 : VenHw(Unknown Device:81)
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blk6 : VenHw(Unknown Device:81)/HD(Part1,Sig00000000)
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blk7 : VenHw(Unknown Device:81)/HD(Part2,Sig00000000)
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blk8 : VenHw(Unknown Device:81)/HD(Part3,Sig00000000)
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blk9 : VenHw(Unknown Device:81)/HD(Part3,Sig00000000)/HD(Part1,Sig00000200)
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blkA : VenHw(Unknown Device:FF)
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blkB : VenHw(Unknown Device:FF)/CDROM(Entry1)
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Shell>
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EDD3.0 is an industry standard and the working draft can be downloaded from the
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following web site:
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http://www.t13.org/
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The document reference is D1386 (Enhanced Disk Drive Services 3.0).
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