0cf321c8 | 01-Mar-2023 |
Daniel Lezcano <daniel.lezcano@linaro.org> |
thermal/drivers/tegra: Remove unneeded lock when setting a trip point
The function tegra_tsensor_enable_hw_channel() takes the thermal zone lock to prevent "a potential" race with a call to set_trip
thermal/drivers/tegra: Remove unneeded lock when setting a trip point
The function tegra_tsensor_enable_hw_channel() takes the thermal zone lock to prevent "a potential" race with a call to set_trips() callback.
The driver must not play with the thermal framework core code internals.
The tegra_tsensor_enable_hw_channel() is called by:
- the suspend / resume callbacks - the probe function after the thermal zones are registered
The thermal zone lock taken in this function is supposed to protect from a call to the set_trips() callback which writes in the same register.
The potential race is when suspend / resume are called at the same time as set_trips. This one is called only in thermal_zone_device_update().
- At suspend time, the 'in_suspend' is set, thus the thermal_zone_device_update() bails out immediately and set_trips is not called during this moment.
- At resume time, the thermal zone is updated at PM_POST_SUSPEND, thus the driver has already set the TH2 temperature.
- At probe time, we register the thermal zone and then we set the TH2. The only scenario I can see so far is the interrupt fires, the thermal_zone_update() is called exactly at the moment tegra_tsensor_enable_hw_channel() a few lines after registering it.
Enable the channels before setting up the interrupt. We close the potential race window without using the thermal zone's lock.
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> Suggested-by: Thierry Reding <thierry.reding@gmail.com> Acked-by: Thierry Reding <treding@nvidia.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
show more ...
|
8f8d8b03 | 17-Jun-2021 |
Dmitry Osipenko <digetx@gmail.com> |
thermal/drivers/tegra: Correct compile-testing of drivers
All Tegra thermal drivers support compile-testing, but the drivers are not available for compile-testing because the whole Kconfig meny entr
thermal/drivers/tegra: Correct compile-testing of drivers
All Tegra thermal drivers support compile-testing, but the drivers are not available for compile-testing because the whole Kconfig meny entry depends on ARCH_TEGRA, missing the alternative COMPILE_TEST dependency option. Correct the Kconfig entry.
Signed-off-by: Dmitry Osipenko <digetx@gmail.com> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> Link: https://lore.kernel.org/r/20210617072403.3487-1-digetx@gmail.com
show more ...
|