Shutdown on thermal HOT event if no userspace tool registered being able to do S4

RFC Thomas Renninger 3 participants 4 messages Mar 30, 2010 – Apr 13, 2010 ACPI

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Thomas Renninger

author

2010-03-30 09:23 UTC #0 lore raw

Hi,

this is related to:
commit fa80945269f312bc609e8384302f58b03c916e12
ACPI thermal: Don't invalidate thermal zone if critical trip point is bad
and
commit 8b7ef6d8f16274da42344cd50746ddb1c93c25ea
ACPI thermal: Check for thermal zone requirement

There the critical trip point is replaced with the hot trip point if latest Windows OS is detected (Vista also? I think yes, but need to double check).

This seem to get more common and it looks like Windows suggests to use hot trip points for thermal emergency shutdowns (S4). It looks like the default Windows thermal emergency power off is S4. Thus the hot trip point is used and the critical trip point is of no use anymore (and often gets replaced or is invalid).

As thermal emergency shut down is something urgent there is this direct call /sbin/poweroff in orderly_poweroff(true) compare with kernel/sys.c and drivers/thermal/thermal_sys.c
This won't work in above cases when BIOS writers assume the machine is shut down with _HOT already and do not provide _CRT anymore.

My idea is to also shutdown the system on _HOT by default, the same way as done if _CRT is exceeded as long as no userspace explicitly set a sysfs (only one file set by thermal_sys.c somewhere in /sys?).
Background is that S4 needs some setup (e.g. swap) or userspace hooks to make sure S4 succeeds and everything (network, whatever...) is set up correctly afterwards.

Requirement for the userspace tool setting the "do not shutdown if a hot thermal event happened" would be:
- Fetch the thermal hot event
- Reliably power off the system (shutdown if S4 did not succeed)
- ...

Comments?
What userspace tools are candidates to implement this if this makes sense?

Thanks,

Thomas

Henrique de Moraes Holschuh

2010-03-31 00:14 UTC #1 lore raw

Quoted 8 lines · Thomas Renninger

My idea is to also shutdown the system on _HOT by default, the same way as done if _CRT is exceeded as long as no userspace explicitly set a sysfs (only one file set by thermal_sys.c somewhere in /sys?).
Background is that S4 needs some setup (e.g. swap) or userspace hooks to make sure S4 succeeds and everything (network, whatever...) is set up correctly afterwards.

Quoted 7 lines

Requirement for the userspace tool setting the "do not shutdown if a hot thermal event happened" would be:
- Fetch the thermal hot event
- Reliably power off the system (shutdown if S4 did not succeed)
- ...
Comments?

ThinkPads have specific alarms that would benefit from a generic interface to report the above stuff to userspace, and to kick a S3/S4/S5 transition if userspace fails to do something about it.

These are:

1. Emergency Thermal alarms (Lenovo tells me we should enter S3 or S4)
- Battery alarm (very dangerous, risk of Lithium fire)
- Sensor alarm (less dangerous, risk of permanent hardware damage)

2. Wakeup from S3 because the battery is nearly empty (enter S4 or S5)
- Pretty much guarantees the user is !@#$#@ if we don't act on it, since it will cause a mess even on a hibernate-to-S3 setup if the user didn't tell the BIOS he does "RediSafe"...

It would be nice to have flags to tell userspace if we want any sleep, or if we need S4/S5.

It would also be nice to have a generic way to deliver these alarms, thinkpads have pre-alarms that should be used to notify the user before things get too dire...

Signature · 4 lines

  "One disk to rule them all, One disk to find them. One disk to bring
  them all and in the darkness grind them. In the Land of Redmond
  where the shadows lie." -- The Silicon Valley Tarot
  Henrique Holschuh

Zhang Rui

2010-04-12 02:37 UTC #2 lore raw

In reply to Thomas Renninger

Quoted 33 lines · Thomas Renninger

Hi,
this is related to:
commit fa80945269f312bc609e8384302f58b03c916e12
ACPI thermal: Don't invalidate thermal zone if critical trip point is bad
and
commit 8b7ef6d8f16274da42344cd50746ddb1c93c25ea
ACPI thermal: Check for thermal zone requirement
There the critical trip point is replaced with the hot trip point if latest Windows OS is detected (Vista also? I think yes, but need to double check).
This seem to get more common and it looks like Windows suggests to use hot trip points for thermal emergency shutdowns (S4). It looks like the default Windows thermal emergency power off is S4. Thus the hot trip point is used and the critical trip point is of no use anymore (and often gets replaced or is invalid).
As thermal emergency shut down is something urgent there is this direct call /sbin/poweroff in orderly_poweroff(true) compare with kernel/sys.c and drivers/thermal/thermal_sys.c
This won't work in above cases when BIOS writers assume the machine is shut down with _HOT already and do not provide _CRT anymore.
My idea is to also shutdown the system on _HOT by default, the same way as done if _CRT is exceeded as long as no userspace explicitly set a sysfs (only one file set by thermal_sys.c somewhere in /sys?).
Background is that S4 needs some setup (e.g. swap) or userspace hooks to make sure S4 succeeds and everything (network, whatever...) is set up correctly afterwards.

Quoted 3 lines

Requirement for the userspace tool setting the "do not shutdown if a hot thermal event happened" would be:
- Fetch the thermal hot event

We need to introduce the notification mechanism, probably via netlink, if we want to do this in the thermal sysfs driver.

Quoted 3 lines

- Reliably power off the system (shutdown if S4 did not succeed)
- ...

Any then introduce another sysfs attribute for each trip point, say "trippoint_x_mode".
kernel driver takes default actions when the threshold is reached when it's set "kernel", and takes no action if it's set "user". users can get the hot event via netlink and take any actions they want..

On the other hand, we can do this in ACPI thermal driver as well. Because
1. netlink event has already been supported.
2. we can disable the kernel action of _HOT by module parameters, say thermal.hot=on(default, s4 or shutdown in kernel)/off(no action, no events)/ignore(no action, but still sends events to userspace).

thanks,
rui

we don't have any notification mechanism in the thermal sys driver currently.
So If we want to do this in the generic thermal driver, we need to introduce the

Quoted 7 lines

Comments?
What userspace tools are candidates to implement this if this makes sense?
Thanks,
Thomas

Thomas Renninger

author

2010-04-13 08:53 UTC #3 lore raw

Hi,

Quoted 38 lines · On Monday 12 April 2010 04:38:14 Zhang Rui wrote:

Quoted 33 lines · Thomas Renninger
Hi,
this is related to:
commit fa80945269f312bc609e8384302f58b03c916e12
ACPI thermal: Don't invalidate thermal zone if critical trip point is bad
and
commit 8b7ef6d8f16274da42344cd50746ddb1c93c25ea
ACPI thermal: Check for thermal zone requirement
There the critical trip point is replaced with the hot trip point if latest Windows OS is detected (Vista also? I think yes, but need to double check).
This seem to get more common and it looks like Windows suggests to use hot trip points for thermal emergency shutdowns (S4). It looks like the default Windows thermal emergency power off is S4. Thus the hot trip point is used and the critical trip point is of no use anymore (and often gets replaced or is invalid).
As thermal emergency shut down is something urgent there is this direct call /sbin/poweroff in orderly_poweroff(true) compare with kernel/sys.c and drivers/thermal/thermal_sys.c
This won't work in above cases when BIOS writers assume the machine is shut down with _HOT already and do not provide _CRT anymore.
My idea is to also shutdown the system on _HOT by default, the same way as done if _CRT is exceeded as long as no userspace explicitly set a sysfs (only one file set by thermal_sys.c somewhere in /sys?).
Background is that S4 needs some setup (e.g. swap) or userspace hooks to make sure S4 succeeds and everything (network, whatever...) is set up correctly afterwards.
Quoted 3 lines
Requirement for the userspace tool setting the "do not shutdown if a hot thermal event happened" would be:
- Fetch the thermal hot event

Quoted 8 lines

We need to introduce the notification mechanism, probably via netlink, if we want to do this in the thermal sysfs driver.
Quoted 3 lines
- Reliably power off the system (shutdown if S4 did not succeed)
- ...
Any then introduce another sysfs attribute for each trip point, say "trippoint_x_mode".

Not sure whether a policy per trip point is really needed.
- active and passive trip points should always be handled in the kernel Eventually notifying userspace might make sense, not sure.
- critical should get handled in kernel as well, the current power_off from kernel isn't that bad and always works.
- Hot is difficult. S4 must get initiated from userspace, but if it fails or especially if you miss the package(s) handling it, your machine will shut off hard with eventuall data loss.

Quoted 11 lines

kernel driver takes default actions when the threshold is reached when it's set "kernel", and takes no action if it's set "user". users can get the hot event via netlink and take any actions they want..
On the other hand, we can do this in ACPI thermal driver as well. Because
1. netlink event has already been supported.
2. we can disable the kernel action of _HOT by module parameters, say thermal.hot=on(default, s4 or shutdown in kernel)/off(no action, no events)/ignore(no action, but still sends events to userspace).

Quoted 4 lines

we don't have any notification mechanism in the thermal sys driver currently.
So If we want to do this in the generic thermal driver, we need to introduce the

This was just a heads up, that critical thermal shut downs may not work with some (a lot?) recent laptops.
IMO it's still not "that" urgent. You could get (more) data loss if your system is switched off hard, than shut down properly (or best suspended). HW damage must still not happen. The point Henrique brought up, with the exploiding battery is a bit of a horror scenario that must never happen.

If I find the time, I'll have a look at the mentioned userspace tools what is already there and come back then (also considering Henriques suggestion of native laptop driver which may want to emergency shutdown/S4 the system for other events than thermal ones).

Thanks for the suggestions,

Thomas