[U-Boot] [PATCH v2 00/22] x86: Add ACPI S3 resume support

[Bin Meng]

Hi Stefan,

On Mon, Apr 24, 2017 at 5:28 PM, Stefan Roese <sr at denx.de> wrote:
> Hi Bin,
>
> On 21.04.2017 16:24, Bin Meng wrote:
>>
>> This adds ACPI S3 (suspend to ram) resume capability in U-Boot.
>> With S3 support within U-Boot, the board wakes up and resumes to
>> OS very quickly.
>>
>> This so far is enabled and tested on Intel MinnowMax board. Please
>> check README.x86 for how to test it with a plain Linux kernel.
>> Linux (w/ or w/o SeaBIOS) and Windows 10 (w/ SeaBIOS) were tested.
>>
>> This series is available for testing at u-boot-x86/s3-working.
>
>
> Thank you very much for working on this. I've started testing this
> patchset on my congatec BayTrail SoM based board. Booting into
> a v4.11-rc based kernel with serial console works just fine.
> Suspend and resume work nicely and fast! :)
>

Thanks for testing!

> Booting Ubuntu 16.04 (kernel 4.4) with graphical interface seems to
> have some (rare) problems though. When I boot into Ubuntu with the
> correct "console=" configuration (log via serial console), suspend
> / resume seems to work fine as well - at least in the tests I did
> so far. But when I don't provide this "console=" and use "quiet"
> instead, resume does not seem to work reliably. Most of the times it
> works just fine as well, but sometimes the graphical user interface
> doesn't come up at all after resuming (display stays in power safe
> mode). The U-Boot log is the same in both cases:
>

I only have a pre-installed Ubuntu 14.04 hard disk which was installed
from U-Boot and SeaBIOS at the time when ACPI/SeaBIOS support was
added to U-Boot long time ago. So suspend/resume does not work with my
installation since I believe Ubuntu has lots of custom scripts for
helping suspend/resume. I've run the testing on this installation
though, and U-Boot did not even boot after I pressed the power button
which means my Ubuntu 14.04 might not even put the system into the
correct ACPI sleeping state. So I have to reinstall a new one.

So how about your Ubuntu 16.04 installation? Was it installed from
U-Boot? Or from original commercial BIOS? What do you mean by "display
stays in power safe mode"? Is it a black screen, or is it just
U-Boot's video output screen?

> Jumping to OS waking vector 0009a1d0
>
> And the POST debug byte is also identical (0x40).
>

These logs looks good. Nothing strange.

> Do you have any ideas, where this might come from? Could you
> perhaps check this on MinnoxMax as well, if such a setup also
> sometimes has problems with resuming? Is there anything that I could
> do to test this on my platform?
>

To match your env, I will install a 16.04 from U-Boot for testing. Can
you add the following kernel parameters for testing suspend/resume?

"console=ttyS0,115200 initcall_debug ignore_loglevel no_console_suspend"

Regards,
Bin