Lukasz, On Fri, Nov 21, 2014 at 09:33:48AM +0100, Lukasz Majewski wrote: > Hi Eduardo, > > > Lukasz, > > > > Thanks for the keeping this up. And apologize for late answer. > > I've already posted v2 of this patch set (which consists of only one > patch :-) ). > > Thanks to Thierry Reding's hint, I've realized that I don't need to add > code from patches 1-6 from v1. > > Please instead review following patch: > "thermal:core:fix: Check return code of the ->get_max_state() callback" > https://patchwork.kernel.org/patch/5326991/ I see. If I got correctly, with the above patch, we still need to have the check for cpufreq driver in the thermal driver right? quoting: "In thermal driver probe the cpufreq_cooling_register() method presence is crucial to evaluate if the thermal driver needs any actions with -EPROBE_DEFER." If yes, that means the proposal still leaves to drivers to deal with the sequencing. For the patch above, I believe it is fine. However, a better sequencing is still needed :-(. For the case of of-thermal based drivers, it should be dealt between cpu_cooling and cpufreq, as I proposed, bellow. I really agree that drivers should not care about this, and thus we should not spread the check among drivers, specially if there is nothing regarding cpufreq in the driver's code. I might send the proposal of having the check between cpu_cooling and cpufreq as a formal patch, in a separated thread. I will have a look in your v2. Briefly looking, looks reasonable. Once again, thanks. Cheers, Eduardo Valentin > > > > > > On Thu, Nov 13, 2014 at 06:02:37PM +0100, Lukasz Majewski wrote: > > > 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: > > > > > > > > > > > > Instead of doing the same check on all drivers in the need for cpu > > cooling looks like a promiscuous solution. What if we do this check in > > cpu cooling itself and we propagate the error in callers code? > > > > From what I see, only exynos does not propagate the error. And we > > would need a tweak in the cpufreq-dt code. Something like the > > following (not tested): > > > > diff --git a/drivers/cpufreq/cpufreq-dt.c > > b/drivers/cpufreq/cpufreq-dt.c index f657c57..f139247 100644 > > --- a/drivers/cpufreq/cpufreq-dt.c > > +++ b/drivers/cpufreq/cpufreq-dt.c > > @@ -181,7 +181,6 @@ static int cpufreq_init(struct cpufreq_policy > > *policy) { > > struct cpufreq_dt_platform_data *pd; > > struct cpufreq_frequency_table *freq_table; > > - struct thermal_cooling_device *cdev; > > struct device_node *np; > > struct private_data *priv; > > struct device *cpu_dev; > > @@ -264,20 +263,6 @@ static int cpufreq_init(struct cpufreq_policy > > *policy) goto out_free_priv; > > } > > > > - /* > > - * For now, just loading the cooling device; > > - * thermal DT code takes care of matching them. > > - */ > > - if (of_find_property(np, "#cooling-cells", NULL)) { > > - cdev = of_cpufreq_cooling_register(np, > > cpu_present_mask); > > - if (IS_ERR(cdev)) > > - dev_err(cpu_dev, > > - "running cpufreq without cooling > > device: %ld\n", > > - PTR_ERR(cdev)); > > - else > > - priv->cdev = cdev; > > - } > > - > > priv->cpu_dev = cpu_dev; > > priv->cpu_reg = cpu_reg; > > policy->driver_data = priv; > > @@ -287,7 +272,7 @@ static int cpufreq_init(struct cpufreq_policy > > *policy) if (ret) { > > dev_err(cpu_dev, "%s: invalid frequency table: > > %d\n", __func__, ret); > > - goto out_cooling_unregister; > > + goto free_table; > > } > > > > policy->cpuinfo.transition_latency = transition_latency; > > @@ -300,8 +285,7 @@ static int cpufreq_init(struct cpufreq_policy > > *policy) > > return 0; > > > > -out_cooling_unregister: > > - cpufreq_cooling_unregister(priv->cdev); > > +free_table: > > dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table); > > out_free_priv: > > kfree(priv); > > @@ -342,11 +326,14 @@ static struct cpufreq_driver dt_cpufreq_driver > > = { > > static int dt_cpufreq_probe(struct platform_device *pdev) > > { > > + struct device_node *np; > > struct device *cpu_dev; > > struct regulator *cpu_reg; > > struct clk *cpu_clk; > > int ret; > > > > + /* at this point we checked the pointer already right? */ > > + np = of_node_get(pdev->dev.of_node); > > /* > > * All per-cluster (CPUs sharing clock/voltages) > > initialization is done > > * from ->init(). In probe(), we just need to make sure that > > clk and @@ -368,6 +355,28 @@ static int dt_cpufreq_probe(struct > > platform_device *pdev) if (ret) > > dev_err(cpu_dev, "failed register driver: %d\n", > > ret); > > + /* > > + * For now, just loading the cooling device; > > + * thermal DT code takes care of matching them. > > + */ > > + if (of_find_property(np, "#cooling-cells", NULL)) { > > + struct cpufreq_policy policy; > > + struct private_data *priv; > > + struct thermal_cooling_device *cdev; > > + > > + /* TODO: can cpu0 be always used ? */ > > + cpufreq_get_policy(&policy, 0); > > + priv = policy.driver_data; > > + cdev = of_cpufreq_cooling_register(np, > > cpu_present_mask); > > + if (IS_ERR(cdev)) > > + dev_err(cpu_dev, > > + "running cpufreq without cooling > > device: %ld\n", > > + PTR_ERR(cdev)); > > + else > > + priv->cdev = cdev; > > + } > > + of_node_put(np); > > + > > return ret; > > } > > > > diff --git a/drivers/thermal/cpu_cooling.c > > b/drivers/thermal/cpu_cooling.c index 1ab0018..342eb9e 100644 > > --- a/drivers/thermal/cpu_cooling.c > > +++ b/drivers/thermal/cpu_cooling.c > > @@ -440,6 +440,11 @@ __cpufreq_cooling_register(struct device_node > > *np, int ret = 0, i; > > struct cpufreq_policy policy; > > > > + if (!cpufreq_get_current_driver()) { > > + dev_warn(&pdev->dev, "no cpufreq driver, > > deferring."); > > + return -EPROBE_DEFER; > > + } > > + > > /* Verify that all the clip cpus have same freq_min, > > freq_max limit */ for_each_cpu(i, clip_cpus) { > > /* continue if cpufreq policy not found and not > > return error */ diff --git > > a/drivers/thermal/samsung/exynos_thermal_common.c > > b/drivers/thermal/samsung/exynos_thermal_common.c index > > 3f5ad25..f84975e 100644 --- > > a/drivers/thermal/samsung/exynos_thermal_common.c +++ > > b/drivers/thermal/samsung/exynos_thermal_common.c @@ -373,7 +373,7 @@ > > int exynos_register_thermal(struct thermal_sensor_conf *sensor_conf) > > if (IS_ERR(th_zone->cool_dev[th_zone->cool_dev_size])) > > { dev_err(sensor_conf->dev, "Failed to register cpufreq cooling > > device\n"); > > - ret = -EINVAL; > > + ret = > > PTR_ERR(th_zone->cool_dev[th_zone->cool_dev_size]); goto > > err_unregister; } > > th_zone->cool_dev_size++; > > > > > > The above way, we avoid having same test in every driver that needs > > it. Besides, it makes sense the cpu_cooling code takes care of this > > check, as it is the very first part that has direct dependency with > > cpufreq. > > > > > 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 > > > > > > > -- > Best regards, > > Lukasz Majewski > > Samsung R&D Institute Poland (SRPOL) | Linux Platform Group
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