| Message ID | 2396230.MApG9VTrxr@wuerfel (mailing list archive) |
|---|---|
| State | Not Applicable, archived |
| Headers | show |
On Fri, Feb 26, 2016 at 2:20 PM, Arnd Bergmann <arnd@arndb.de> wrote: > On Friday 26 February 2016 12:04:59 Li Yang wrote: >> On Fri, Dec 18, 2015 at 4:32 PM, Arnd Bergmann <arnd@arndb.de> wrote: >> > On Tuesday 15 December 2015 00:58:26 Rafael J. Wysocki wrote: >> >> On Thursday, November 26, 2015 05:21:11 PM Jia Hongtao wrote: >> >> > Register the qoriq cpufreq driver as a cooling device, based on the >> >> > thermal device tree framework. When temperature crosses the passive trip >> >> > point cpufreq is used to throttle CPUs. >> >> > >> >> > Signed-off-by: Jia Hongtao <hongtao.jia@freescale.com> >> >> > Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org> >> >> >> >> Applied, thanks! >> >> >> > >> > I got a randconfig build error today: >> > >> > drivers/built-in.o: In function `qoriq_cpufreq_ready': >> > debugfs.c:(.text+0x1f4688): undefined reference to `of_cpufreq_cooling_register' >> > >> > CONFIG_OF=y >> > CONFIG_QORIQ_CPUFREQ=y >> > CONFIG_THERMAL=m >> > CONFIG_THERMAL_OF=y >> > >> > I think you need a 'depends on THERMAL' to prevent the driver from >> > being built-in when THERMAL=m. >> >> Maybe this is not the best approach. The cpufreq feature itself >> should be working independently without thermal framework. I think we >> should make the qoriq_cpufreq_ready() defined as null function if >> THERMAL is not defined. > > It already does this when CONFIG_THERMAL is not defined, and my > patch doesn't change that. I'm not sure what you are asking for now. Oh. Actually I didn't see you just sent a patch for this. I accidentally get into this topic when I tried to find out why cpufreq is not working on ARMv8 platforms. I didn't notice that of_cpufreq_cooling_register() is already ifdef-ed. > > Do you want to allow using the cpufreq driver as a built-in driver > even when the thermal code is in a module, and then silently skip > all thermal management as if it was turned off? Having thermal code to be built as module and qoriq_cpufreq to be built-in is a valid situation. Making cpufreq not possible to be used when thermal is a module doesn't seem to be right. > > That would be this patch: > > diff --git a/include/linux/cpu_cooling.h b/include/linux/cpu_cooling.h > index c156f5082758..a8d9241fc1bb 100644 > --- a/include/linux/cpu_cooling.h > +++ b/include/linux/cpu_cooling.h > @@ -48,7 +48,7 @@ cpufreq_power_cooling_register(const struct cpumask *clip_cpus, > * @np: a valid struct device_node to the cooling device device tree node. > * @clip_cpus: cpumask of cpus where the frequency constraints will happen > */ > -#ifdef CONFIG_THERMAL_OF > +#if IS_REACHABLE(CONFIG_THERMAL_OF) > struct thermal_cooling_device * > of_cpufreq_cooling_register(struct device_node *np, > const struct cpumask *clip_cpus); > > > but my feeling is that this would cause more surprises when users > find their thermal management is not active even though it was > enabled in Kconfig and the thermal module gets loaded. I don't have a perfect solution either. But I think this is still better than making cpufreq not usable. The cpufreq driver will print out an error message if thermal is not reachable. Maybe this can relief the confusion a little bit? Regards, Leo -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Friday 26 February 2016 17:07:09 Li Yang wrote: > > I don't have a perfect solution either. But I think this is still > better than making cpufreq not usable. The cpufreq driver will print > out an error message if thermal is not reachable. Maybe this can > relief the confusion a little bit? With my patch, the configuration will just force the cpufreq driver to be a loadable module as well if thermal is a module, so the dependency can be resolved by loading the thermal module first. I think that is really the best way around the problem, and it matches what other platforms do for the same problem. Arnd -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/include/linux/cpu_cooling.h b/include/linux/cpu_cooling.h index c156f5082758..a8d9241fc1bb 100644 --- a/include/linux/cpu_cooling.h +++ b/include/linux/cpu_cooling.h @@ -48,7 +48,7 @@ cpufreq_power_cooling_register(const struct cpumask *clip_cpus, * @np: a valid struct device_node to the cooling device device tree node. * @clip_cpus: cpumask of cpus where the frequency constraints will happen */ -#ifdef CONFIG_THERMAL_OF +#if IS_REACHABLE(CONFIG_THERMAL_OF) struct thermal_cooling_device * of_cpufreq_cooling_register(struct device_node *np, const struct cpumask *clip_cpus);