[U-Boot] [PATCH v2 00/28] x86: Initial ACPI support for Intel BayTrail

[Bin Meng]

Hi Simon,

On Sun, May 8, 2016 at 2:45 AM, Simon Glass <sjg at chromium.org> wrote:
> Hi Bin,
>
> On 7 May 2016 at 08:46, Bin Meng <bmeng.cn at gmail.com> wrote:
>> This series introduces initial ACPI support for Intel BayTrail.
>>
>> Advanced Configuration and Power Interface (ACPI) aims to establish
>> industry-standard interfaces enabling OS-directed configuration, power
>> management, and thermal management of mobile, desktop, and server platforms.
>>
>> Linux can boot without ACPI with "acpi=off" command line parameter, but
>> with ACPI the kernel gains the capabilities to handle power management.
>> For Windows, ACPI is a must-have firmware feature since Windows Vista.
>> CONFIG_GENERATE_ACPI_TABLE is the config option to turn on ACPI support in
>> U-Boot. This requires Intel ACPI compiler to be installed on your host to
>> compile ACPI DSDT table written in ASL format to AML format. You can get
>> the compiler via "apt-get install iasl" if you are on Ubuntu or download
>> the source from acpica website to compile one by yourself.
>>
>> Current ACPI support in U-Boot is not complete. More features will be added
>> in the future. The status as of today is:
>>
>>  * Support generating RSDT, XSDT, FACS, FADT, MADT, MCFG tables.
>>  * Support one static DSDT table only, compiled by Intel ACPI compiler.
>>  * Support S0/S5, reboot and shutdown from OS.
>>  * Support booting a pre-installed Ubuntu distribution via 'zboot' command.
>>  * Support ACPI interrupts with SCI only.
>>
>> Features not supported so far (to make it a complete ACPI solution):
>>  * S3 (Suspend to RAM), S4 (Suspend to Disk).
>>  * Install and boot Ubuntu 14.04 (or above) from U-Boot with legacy interface.
>>  * Install and boot Windows 8.1/10 from U-Boot with legacy interface.
>>
>> Features that are optional:
>>  * ACPI global NVS support. We may need it to simplify ASL code logic if
>>    utilizing NVS variables. Most likely we will need this sooner or later.
>>  * Dynamic AML bytecodes insertion at run-time. We may need this to support
>>    SSDT table generation and DSDT fix up.
>>  * SMI support. Since U-Boot is a modern bootloader, we don't want to bring
>>    those legacy stuff into U-Boot. ACPI spec allows a system that does not
>>    support SMI (a legacy-free system).
>>
>> So far ACPI is enabled on BayTrail based boards. Testing was done by booting
>> a pre-installed Ubuntu 14.04 from a SATA drive. Most devices seem to work
>> correctly and the board can respond a reboot/shutdown command from Ubuntu.
>
> It's great to see this - a big step forward!
>

Thanks for the review.

> A few general comments:
> - when building, the Intel ACPI tools output some non-warning info -
> can you quieten this down? It should not appear when 'make -s' is used

Sure.

> - is it OK to enable other tables along with ACPI? The docs seem to be
> silent on this point

I believe other tables are optional, as Linux can boot now. But maybe
there are some tables that Windows need. I will continue working on
this.

> - for me Ubuntu does not offer an option in the GUI to restart...I can
> do it from the command line. On my normal desktop I see a power button
> in the top right. I wonder why this doesn't work on minnowmax?
>

Maybe there are some issues with your installation? I can see a power
button in the top right on my minnowmax. I installed Ubuntun 14.04.4
64-bit OS (http://releases.ubuntu.com/14.04/ubuntu-14.04.4-desktop-amd64.iso)
with the original UEFI BIOS on the board.

[snip]

Regards,
Bin