Attention is currently required from: Furquan Shaikh, Martin Roth, Tim Wawrzynczak, Rob Barnes. Raul Rangel has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/54134 )
Change subject: mb/google/guybrush: Add SoC thermal zone ......................................................................
Patch Set 1:
(1 comment)
File src/mainboard/google/guybrush/variants/baseboard/devicetree.cb:
https://review.coreboot.org/c/coreboot/+/54134/comment/d73a83dd_76ed367f PS1, Line 55: chip drivers/acpi/thermal_zone : register "name" = ""SOC"" : : register "temperature_sensor_id" = "0" : : register "polling_period" = "10000" : : # EC is configured to power off the system at 92C, so add one degree of buffer : # so the OS can gracefully shutdown : register "critical_temperature" = "91" : : # EC is configured to assert PROCHOT at 90C. That drastically lowers : # performance. Instead we will tell the OS to start throttling the CPUs at : # 85C in hopes that we don't hit the PROCHOT limit. : register "passive_config" = "{ : .temperature = 85, : .time_constant_1 = 2, : .time_constant_2 = 5, : .time_sampling_period = 2000, : }" : : device generic 0 on end : end I thought about placing it under the EC, but I wasn't quite convinced:
A thermal zone may be declared in the namespace anywhere within the _SB scope. For compatibility with operating systems implementing ACPI 1.0, a thermal zone may also be declared under the _TZ scope. An ACPI-compatible namespace may define Thermal Zone objects in either the _SB or _TZ scope but not both.
My thought was that if the device was placed under the EC, it would generate the ThermalZone as a child of the EC, but if it was in the root, it would be added to the _TZ scope.
I would ideally like it under the EC, but [ec.asl](https://source.chromium.org/chromiumos/chromiumos/codesearch/+/main:src/thir...) does a `Notify (_TZ, 0x80)`, so I need to add them to the _TZ.
Though, I wonder if a `Notify(EC0, 0x80)` would cause the OS to reevaluate the child ThermalZones...