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@titlepage
@title ThinkPad T400
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@node Top
@top ThinkPad T400

@menu
* ThinkPad T400::
* LCD compatibly::
@end menu

@node ThinkPad T400
@chapter ThinkPad T400
@anchor{#thinkpad-t400}
It is believed that all or most T400 laptops are compatible. See notes about @uref{../install/t400_external.html#cpu_compatibility,CPU compatibility} for potential incompatibilities.

There are two possible flash chip sizes for the T400: 4MiB (32Mbit) or 8MiB (64Mbit). This can be identified by the type of flash chip below the palmrest: 4MiB is SOIC-8, 8MiB is SOIC-16.

@strong{The T400 laptops come with the ME (and sometimes AMT in addition) before flashing libreboot. Libreboot disables and removes it by using a modified descriptor: see @uref{gm45_remove_me.html,gm45_remove_me.html}} (contains notes, plus instructions)

Flashing instructions can be found at @uref{../install/index.html#flashrom,../install/index.html#flashrom}

@uref{index.html,Back to previous index}.
@menu
* Compatibility without blobs::
@end menu

@node Compatibility without blobs
@section Compatibility (without blobs)
@anchor{#compatibility-without-blobs}
@menu
* Hardware virtualization vt-x::
@end menu

@node Hardware virtualization vt-x
@subsection Hardware virtualization (vt-x)
@anchor{#hardware-virtualization-vt-x}
The T400, when run without CPU microcode updates in coreboot, currently kernel panics if running QEMU with vt-x enabled on 2 cores for the guest. With a single core enabled for the guest, the guest panics (but the host is fine). Working around this in QEMU might be possible; if not, software virtualization should work fine (it's just slower).

On GM45 hardware (with libreboot), make sure that the @emph{kvm} and @emph{kvm_intel} kernel modules are not loaded, when using QEMU.

The following errata datasheet from Intel might help with investigation: @uref{http://download.intel.com/design/mobile/specupdt/320121.pdf,http://download.intel.com/design/mobile/specupdt/320121.pdf}

The T400 is almost identical to the X200, code-wise. See @uref{x200.html,x200.html}.

@node LCD compatibly
@chapter LCD compatibly
@anchor{#lcd-compatibly}
Not all LCD panels are compatible yet. See @uref{gm45_lcd.html,gm45_lcd.html}.
@menu
* Hardware register dumps::
@end menu

@node Hardware register dumps
@section Hardware register dumps
@anchor{#hardware-register-dumps}
The coreboot wiki @uref{http://www.coreboot.org/Motherboard_Porting_Guide,shows} how to collect various logs useful in porting to new boards. Following are outputs from the T400:

@itemize
@item
T400 with @strong{Winbond W25X64} flash chip (8MiB, SOIC-16) and Lenovo BIOS 2.02 (EC firmware 1.01):
@itemize
@item
@uref{../resources/misc/dumps/logs-t400-bios2.02-ec1.01/,../resources/misc/dumps/logs-t400-bios2.02-ec1.01/}
@end itemize

@item
Version of flashrom used for the external flashing/reading logs is the one that libreboot git revision c164960 uses.
@end itemize

Copyright © 2015 Minifree Ltd <info@@minifree.org>@* Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license can be found at @uref{../resources/licenses/gfdl-1.3.txt,gfdl-1.3.txt}

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