Change in ...coreboot[master]: sb/amd/cimx/sb800: Get rid of power button device in coreboot

[Paul Menzel (Code Review)]

Hello Kyösti Mälkki, Piotr Król, Stefan Reinauer, build bot (Jenkins), Michał Żygowski,

I'd like you to reexamine a change. Please visit

https://review.coreboot.org/c/coreboot/+/27496

to look at the new patch set (#5).

Change subject: sb/amd/cimx/sb800: Get rid of power button device in coreboot
......................................................................

sb/amd/cimx/sb800: Get rid of power button device in coreboot

Apply commit d7b88dcb (mb/google/x86-boards: Get rid of power button
device in coreboot) to AMD Brazos boards [1]:
> As per the ACPI specification, there are two types of power button
> devices:
> Fixed hardware power button
> Generic hardware power button
>
> Fixed hardware power button is added by the OSPM if POWER_BUTTON flag
> is not set in FADT by the BIOS. This device has its programming model
> in PM1x_EVT_BLK. All ACPI compliant OSes are expected to add this
> power button device by default if the power button FADT flag is not
> set.
>
> On the other hand, generic hardware power button can be used by
> platforms if fixed register space cannot be used for the power button
> device. In order to support this, power button device object with HID
> PNP0C0C is expected to be added to ACPI tables. Additionally,
> POWER_BUTTON flag should be set to indicate the presence of control
> method for power button.
>
> Chrome EC mainboards implemented the generic hardware power button in
> a broken manner i.e. power button object with HID PNP0C0C is added to
> ACPI however none of the boards set POWER_BUTTON flag in FADT. This
> results in Linux kernel adding both fixed hardware power button as
> well as generic hardware power button to the list of devices present
> on the system. Though this is mostly harmless, it is logically
> incorrect and can confuse any userspace utilities scanning the ACPI
> devices.
>
> This change gets rid of the generic hardware power button from all
> google mainboards and relies completely on the fixed hardware power
> button.

The same problem exists with the AMD Hudson devices in coreboot.

For AMD Hudson (2) and Yangtze based devices this was removed in commit
44f2fab8 (AMD hudson and yangtze boards: Let mainboard declare power
button) [2].

Two devices are detected.

$ dmesg | grep Button
    [    0.209213] input: Power Button as /devices/LNXSYSTM:00/LNXSYBUS:00/PNP0C0C:00/input/input0
    [    0.209254] ACPI: Power Button [PWRB]
    [    0.209332] input: Power Button as /devices/LNXSYSTM:00/LNXPWRBN:00/input/input1
    [    0.209349] ACPI: Power Button [PWRF]
    $ sudo evtest
    No device specified, trying to scan all of /dev/input/event*
    Available devices:
    /dev/input/event0:      Power Button
    /dev/input/event1:      Power Button
    /dev/input/event2:      AT Translated Set 2 keyboard
    /dev/input/event3:      HD-Audio Generic HDMI/DP,pcm=3
    /dev/input/event4:      HDA ATI SB Rear Mic
    /dev/input/event5:      HDA ATI SB Front Mic
    /dev/input/event6:      HDA ATI SB Line
    /dev/input/event7:      HDA ATI SB Line Out Front
    /dev/input/event8:      HDA ATI SB Line Out Surround
    /dev/input/event9:      HDA ATI SB Line Out CLFE
    /dev/input/event10:     HDA ATI SB Line Out Side
    /dev/input/event11:     HDA ATI SB Front Headphone
    /dev/input/event12:     HID 1241:1122

Enumerating these devices also takes time in user space programs.

$ journalctl -o short-precise -u systemd-logind.service -b
    -- Logs begin at Sat 2017-12-16 23:28:06 CET, end at Mon 2018-07-16 08:23:11 CEST. --
    Jul 16 08:22:54.006190 kodi systemd[1]: Starting Login Service...
    Jul 16 08:22:54.103445 kodi systemd-logind[169]: New seat seat0.
    Jul 16 08:22:54.163713 kodi systemd[1]: Started Login Service.
    Jul 16 08:22:54.312955 kodi systemd-logind[169]: Watching system buttons on /dev/input/event1 (Power Button)
    Jul 16 08:22:54.514965 kodi systemd-logind[169]: Watching system buttons on /dev/input/event0 (Power Button)
    Jul 16 08:22:54.781082 kodi systemd-logind[169]: Watching system buttons on /dev/input/event2 (AT Translated Set 2 keyboard)

With this commit, only one button device needs to be dealt with.

$ journalctl -o short-precise -u systemd-logind.service -b
    -- Logs begin at Sat 2017-12-16 23:28:06 CET, end at Mon 2018-07-16 09:11:03 CEST. --
    Jul 16 09:10:23.998910 kodi systemd[1]: Starting Login Service...
    Jul 16 09:10:24.069152 kodi systemd-logind[168]: New seat seat0.
    Jul 16 09:10:24.196628 kodi systemd[1]: Started Login Service.
    Jul 16 09:10:24.470667 kodi systemd-logind[168]: Watching system buttons on /dev/input/event0 (Power Button)
    Jul 16 09:10:24.853909 kodi systemd-logind[168]: Watching system buttons on /dev/input/event1 (AT Translated Set 2 keyboard)

[1]: https://review.coreboot.org/5546
[2]: https://review.coreboot.org/27272

Change-Id: I0cbecb72f7e1bf3d051d3b7656c6af4d6f43b497
Signed-off-by: Paul Menzel 
---
M src/mainboard/amd/inagua/acpi/gpe.asl
M src/mainboard/amd/persimmon/acpi/gpe.asl
M src/mainboard/amd/south_station/acpi/gpe.asl
M src/mainboard/amd/union_station/acpi/gpe.asl
M src/mainboard/asrock/e350m1/acpi/gpe.asl
M src/mainboard/elmex/pcm205400/acpi/gpe.asl
M src/mainboard/gizmosphere/gizmo/acpi/gpe.asl
M src/mainboard/jetway/nf81-t56n-lf/acpi/gpe.asl
M src/mainboard/pcengines/apu1/acpi/gpe.asl
M src/southbridge/amd/cimx/sb800/acpi/fch.asl
10 files changed, 0 insertions(+), 90 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/96/27496/5