Hi Eduardo, > 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." Yes we need those checks in thermal drivers. However, proper checks are already in place - please look into imx_thermal.c case. > > 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 :-(. There is always a trade off. What I've shown in v2 is that I'm pretty confident that my fix won't introduce any regression for present code. > > 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, Unfortunately several checks are already in place (imx_thermal.c, db8500_cpufreq.c, ti-soc*.c, in some way the old Exynos thermal driver). > specially if there is nothing regarding cpufreq > in the driver's code. There is a call to cpufreq_cooling_register(), which sometimes happens in the late part of probe function. In such a case it would be quite challenging to release already allocated resources (e.g. ti, old Exynos driver). > I might send the proposal of having the check > between cpu_cooling and cpufreq as a formal patch, in a separated > thread. It would be beneficial to hear Viresh's opinion. > > I will have a look in your v2. Briefly looking, looks reasonable. In short: The goal of this patch is to show that regressions should not happen and that it can be safely applied for v3.19. > > > 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 -- Best regards, Lukasz Majewski Samsung R&D Institute Poland (SRPOL) | Linux Platform Group -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
