| Message ID | eaf4ab5f-2ce1-4e87-a31c-f2b5ebd15c19@suse.com |
|---|---|
| State | New |
| Headers | show |
| Series | [RFC] docs: thermal/drivers/intel: Reading trip point previously set to 0 | expand |
Hi Vasilis, On Thu, 2023-09-28 at 20:05 +0200, Vasilis LIaskovitis wrote: > Hi, > > ping, any thoughts on this? > > > Since commit: > > eb8500b8 "thermal/drivers/intel: Initialize RW trip to > > THERMAL_TEMP_INVALID" > > > > writing 0 into thermal trip point temp sysfs files cannot be read > > back: > > ~ # echo 0 > > > /sys/devices/virtual/thermal/thermal_zone1/trip_point_0_temp > > ~ # cat > > /sys/devices/virtual/thermal/thermal_zone1/trip_point_0_temp > > -274000 > > > > Prior to this change, the value 0 could be "read". Afaict only > > because > > 0 was always returned for uninitialized trip points, and not only > > when > > 0 was actually written into the trip_point_*_temp by userspace. > > > > A customer uses scripts to set the trip_point_*_temp value to 0, > > and > > then checks that the value is indeed 0. Their userspace test suite > > breaks because of this change. > > > > Should userspace still be able to read the set value of 0 (meaning > > the > > thermal subsystem confirms no notifications will be sent)? I > > understand this is a corner case (maybe it's even non-sensical to > > check a value of 0 is returned, after setting it), but I wanted to > > ask > > since the sysfs value read by userspace is now > > THERMAL_TEMP_INVALID. > > > > Or should we instead update documentation to reflect the fact that > > uninitialized trip points and trip points set to 0 return an > > invalid > > value THERMAL_TEMP_INVALID? E.g.: > > I think better to update documentation, Please submit a change, if you can. Thanks, Srinivas > > > > diff --git > > a/Documentation/driver-api/thermal/x86_pkg_temperature_thermal.rst > > b/Documentation/driver-api/thermal/x86_pkg_temperature_thermal.rst > > index 2ac42ccd236f6..2e6f2728b5b94 100644 > > --- a/Documentation/driver- > > api/thermal/x86_pkg_temperature_thermal.rst > > +++ b/Documentation/driver- > > api/thermal/x86_pkg_temperature_thermal.rst > > @@ -43,8 +43,10 @@ User can set any temperature between 0 to TJ-Max > > temperature. Temperature units > > are in milli-degree Celsius. Refer to > > "Documentation/driver-api/thermal/sysfs-api.rst" for > > thermal sys-fs details. > > > > +An uninitialized trip_point_*_temp returns an invalid value > > (THERMAL_TEMP_INVALID). > > Any value other than 0 in these trip points, can trigger thermal > > notifications. > > -Setting 0, stops sending thermal notifications. > > +Setting 0, stops sending thermal notifications. Having set 0, the > > value returned by the > > +trip point remains invalid (THERMAL_TEMP_INVALID). > > > > Thermal notifications: > > To get kobject-uevent notifications, set the thermal zone > >
diff --git a/Documentation/driver-api/thermal/x86_pkg_temperature_thermal.rst b/Documentation/driver-api/thermal/x86_pkg_temperature_thermal.rst index 2ac42ccd236f6..2e6f2728b5b94 100644 --- a/Documentation/driver-api/thermal/x86_pkg_temperature_thermal.rst +++ b/Documentation/driver-api/thermal/x86_pkg_temperature_thermal.rst @@ -43,8 +43,10 @@ User can set any temperature between 0 to TJ-Max temperature. Temperature units are in milli-degree Celsius. Refer to "Documentation/driver-api/thermal/sysfs-api.rst" for thermal sys-fs details. +An uninitialized trip_point_*_temp returns an invalid value (THERMAL_TEMP_INVALID). Any value other than 0 in these trip points, can trigger thermal notifications. -Setting 0, stops sending thermal notifications. +Setting 0, stops sending thermal notifications. Having set 0, the value