a39a812e40
The PCH's SGPIO pads are connected to a buffer chip that is powered from
the always-on +3V3_AUX rail. For some cursed reason, when the SGPIO pads
stay configured as SGPIO when a Poseidon system shuts down, voltage from
the +3V3_AUX-powered buffer chip will leak into the +5V rail through the
SATA backplane. Just pulling the SGPIO pads low before the system powers
off stops the +5V rail from being cross-powered.
This issue has only been observed in S5, but it's very likely other
sleep states are affected as well. Thus, always pull the SGPIO pins
low before entering ACPI S3 or deeper because the power supply will
turn off in these states as well.
TEST=Obtain a Poseidon system, verify that the +5V rail is cross-powered
after going to S5. We measured 0.17V on our system, but voltages as
high as 0.6V were measured on other systems. Verify that unplugging
the SGPIO cable going to the SATA backplane results in the +5V rail
voltage dropping to 0V, which indicates that the voltage leakage is
exclusively coming from the SGPIO and SATA backplane. Finally, make
sure that the +5V rail voltage drops to 0V after going into ACPI S5
with this patch applied and the SGPIO cable connected.
Change-Id: Ic872903d5fcdd1c17e02b4c06d5ba29889fbc27d
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/66616
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Lean Sheng Tan <sheng.tan@9elements.com>
|
||
|---|---|---|
| 3rdparty | ||
| configs | ||
| Documentation | ||
| LICENSES | ||
| payloads | ||
| spd | ||
| src | ||
| tests | ||
| util | ||
| .checkpatch.conf | ||
| .clang-format | ||
| .editorconfig | ||
| .gitignore | ||
| .gitmodules | ||
| .gitreview | ||
| .mailmap | ||
| AUTHORS | ||
| COPYING | ||
| gnat.adc | ||
| MAINTAINERS | ||
| Makefile | ||
| Makefile.inc | ||
| README.md | ||
| toolchain.inc | ||
coreboot README
coreboot is a Free Software project aimed at replacing the proprietary BIOS (firmware) found in most computers. coreboot performs a little bit of hardware initialization and then executes additional boot logic, called a payload.
With the separation of hardware initialization and later boot logic, coreboot can scale from specialized applications that run directly firmware, run operating systems in flash, load custom bootloaders, or implement firmware standards, like PC BIOS services or UEFI. This allows for systems to only include the features necessary in the target application, reducing the amount of code and flash space required.
coreboot was formerly known as LinuxBIOS.
Payloads
After the basic initialization of the hardware has been performed, any desired "payload" can be started by coreboot.
See https://www.coreboot.org/Payloads for a list of supported payloads.
Supported Hardware
coreboot supports a wide range of chipsets, devices, and mainboards.
For details please consult:
Build Requirements
- make
- gcc / g++
Because Linux distribution compilers tend to use lots of patches. coreboot
does lots of "unusual" things in its build system, some of which break due
to those patches, sometimes by gcc aborting, sometimes - and that's worse -
by generating broken object code.
Two options: use our toolchain (eg. make crosstools-i386) or enable the
ANY_TOOLCHAINKconfig option if you're feeling lucky (no support in this case). - iasl (for targets with ACPI support)
- pkg-config
- libssl-dev (openssl)
Optional:
- gdb (for better debugging facilities on some targets)
- ncurses (for
make menuconfigandmake nconfig) - flex and bison (for regenerating parsers)
Building coreboot
Please consult https://www.coreboot.org/Build_HOWTO for details.
Testing coreboot Without Modifying Your Hardware
If you want to test coreboot without any risks before you really decide to use it on your hardware, you can use the QEMU system emulator to run coreboot virtually in QEMU.
Please see https://www.coreboot.org/QEMU for details.
Website and Mailing List
Further details on the project, a FAQ, many HOWTOs, news, development guidelines and more can be found on the coreboot website:
You can contact us directly on the coreboot mailing list:
https://www.coreboot.org/Mailinglist
Copyright and License
The copyright on coreboot is owned by quite a large number of individual developers and companies. Please check the individual source files for details.
coreboot is licensed under the terms of the GNU General Public License (GPL). Some files are licensed under the "GPL (version 2, or any later version)", and some files are licensed under the "GPL, version 2". For some parts, which were derived from other projects, other (GPL-compatible) licenses may apply. Please check the individual source files for details.
This makes the resulting coreboot images licensed under the GPL, version 2.