Presented fixes are a response for problem described below:
http://thread.gmane.org/gmane.linux.kernel/1793821/match=thermal+core+fix+initialize+max_state+variable+0
In short - it turned out that two trivial fixes (included in this patch set)
require support for deferred probe in thermal drivers.
This situation shows up when CPU frequency reduction is used as a thermal
cooling
device for a thermal zone.
It happens that during initialization, the call to thermal probe will be
executed
before cpufreq probe (it can be observed at ./drivers/Makefile).
In such a situation thermal will not be properly configured until cpufreq policy
is setup.
In the current code (without included fixes) there is a time window in which
thermal
can try to use not configured cpufreq and possibly crash the system.
Proposed solution was based on the code already available in the imx_thermal.c
file.
/db8500_thermal.c: -> NOT NEEDED
/intel_powerclamp.c: -> NOT NEEDED - INTEL (x86)
/intel_powerclamp.c: -> NOT NEEDED - INTEL (x86)
/ti-soc-thermal/ti-bandgap.c: -> FIXED [omap2plus_defconfig]
/dove_thermal.c: -> NOT NEEDED - CPU_COOLING NOT
AVAILABLE
[dove_defconfig]
/spear_thermal.c: -> FIXED [spear3xx_defconfig]
/samsung/exynos_tmu.c: -> NOT NEEDED (nasty hack - will be
reworked in later patches)
/imx_thermal.c: -> OK (deferred probe already in place)
/int340x_thermal/int3402_thermal.c: -> NOT NEEDED - ACPI x86 - Intel
specific
/int340x_thermal/int3400_thermal.c: -> NOT NEEDED - ACPI x86 - Intel
specific
/tegra_soctherm.c: -> FIXED [tegra_defconfig]
/kirkwood_thermal.c: -> FIXED [multi_v5_defconfig]
/armada_thermal.c: -> FIXED [multi_v7_defconfig]
/rcar_thermal.c: -> FIXED [shmobile_defconfig]
/db8500_cpufreq_cooling.c: -> OK (deferred probe already in place)
[multi_v7_defconfig]
/st/st_thermal_syscfg.c: -> NOT NEEDED (Those two are enabled by
e.g. ARMADA)
/st/st_thermal_memmap.c:
I only possess Exynos boards and Beagle Bone Black, so I'd be grateful for
testing proposed solution on other boards. The posted code is compile tested.
This code applies on Eduardo's ti-soc-thermal-next tree:
SHA1: 208a97042d66d9bfbcfab0d4a00c9fe317bb73d3
Lukasz Majewski (8):
thermal:cpu cooling:armada: Provide deferred probing for armada driver
thermal:cpu cooling:kirkwood: Provide deferred probing for kirkwood
driver
thermal:cpu cooling:rcar: Provide deferred probing for rcar driver
thermal:cpu cooling:spear: Provide deferred probing for spear driver
thermal:cpu cooling:tegra: Provide deferred probing for tegra driver
thermal:cpu cooling:ti: Provide deferred probing for ti drivers
thermal:core:fix: Initialize the max_state variable to 0
thermal:core:fix: Check return code of the ->get_max_state() callback
drivers/thermal/armada_thermal.c | 7 +++++++
drivers/thermal/kirkwood_thermal.c | 7 +++++++
drivers/thermal/rcar_thermal.c | 7 +++++++
drivers/thermal/spear_thermal.c | 7 +++++++
drivers/thermal/tegra_soctherm.c | 7 +++++++
drivers/thermal/thermal_core.c | 8 +++++---
drivers/thermal/ti-soc-thermal/ti-bandgap.c | 7 +++++++
7 files changed, 47 insertions(+), 3 deletions(-)
--
2.0.0.rc2
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