tree 1de4c3f5587f3df8621bfdaf9de12e78fff447fb
parent e5f98896efb3b6350cb6f1c241394966dcbcf240
author Rafael J. Wysocki <rafael.j.wysocki@intel.com> 1721329274 +0200
committer Rafael J. Wysocki <rafael.j.wysocki@intel.com> 1721817623 +0200

thermal: core: Back off when polling thermal zones on errors

Commit a8a261774466 ("thermal: core: Call monitor_thermal_zone() if zone
temperature is invalid") introduced a polling mechanism by which the
thermal core attampts to get a valid temperature value for thermal zones
where the .get_temp() callback returns errors to start with (for
example, due to initialization ordering woes).  However, this polling is
carried out periodically ad infinitum and every iteration of it causes
a message to be printed to the kernel log which means a lot of log noise
on systems where there are thermal zones that never get ready for some
reason.  It is also not really useful to continuously poll thermal zones
that never respond.

To address this, modify the thermal core to increase the delay between
consecutive thermal zone temperature checks after every check that fails
until it reaches a certain maximum value.  At that point, the thermal
zone in question will be disabled, but user space will be able to
reenable it if it believes that the failure is transient.

Also change the code to print messages regarding failed temperature
checks to the kernel log only twice, once when the thermal zone's
.get_temp() callback returns an error for the first time and once when
disabling the given thermal zone.  In addition, a dev_crit() message
will be printed at that point if the given thermal zone contains a
critical trip point to notify the system operator about the situation.

Fixes: a8a261774466 ("thermal: core: Call monitor_thermal_zone() if zone temperature is invalid")
Link: https://lore.kernel.org/linux-acpi/CAGnHSE=RyPK++UG0-wAtVKgeJxe0uzFYgLxm+RUOKKoQquW=Ow@mail.gmail.com/
Reported-by: Tom Yan <tom.ty89@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://patch.msgid.link/2962033.e9J7NaK4W3@rjwysocki.net