| Message ID | c73c825beda0207867bd29e40fece217cbf15925.1400736536.git.viresh.kumar@linaro.org |
|---|---|
| State | New |
| Headers | show |
Hello Viresh, On Thu, May 22, 2014 at 11:07:25AM +0530, Viresh Kumar wrote: > cpufreq-cpu0 uses thermal framework to register a cooling device, but doesn't > depend on it as there are dummy calls provided by thermal layer when > CONFIG_THERMAL=n. So, we don't really need to mention thermal as a dependency > for cpufreq-cpu0 in Kconfig. I see your point. > > Remove it. However, on CPUs that needs thermal managment, it makes sense to have such dependency, from functional perspective. Mainly because scaling frequency and voltage up would be allowed only when thermal management is enabled. > > Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> > --- > drivers/cpufreq/Kconfig | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/cpufreq/Kconfig b/drivers/cpufreq/Kconfig > index 1fbe11f..4310997 100644 > --- a/drivers/cpufreq/Kconfig > +++ b/drivers/cpufreq/Kconfig > @@ -185,7 +185,7 @@ config CPU_FREQ_GOV_CONSERVATIVE > > config GENERIC_CPUFREQ_CPU0 > tristate "Generic CPU0 cpufreq driver" > - depends on HAVE_CLK && REGULATOR && OF && THERMAL && CPU_THERMAL > + depends on HAVE_CLK && REGULATOR && OF > select PM_OPP > help > This adds a generic cpufreq driver for CPU0 frequency management. > -- > 2.0.0.rc2 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ -- 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 22 May 2014 20:22, Eduardo Valentin <edubezval@gmail.com> wrote: > However, on CPUs that needs thermal managment, it makes sense to have > such dependency, from functional perspective. Mainly because scaling > frequency and voltage up would be allowed only when thermal management > is enabled. AFAIK, dependencies in KCONFIG are only for fixing compilation time issues. As some APIs wouldn't be available without enabling some config options.. If drivers fail at runtime because some API returned error, fix it for your platform instead and not bug KCONFIG for that. Thought we might consider some runtime dependencies here as well. For example regulators. There probably are dummy routine available for cases where CONFIG_REGULATOR (or whatever) isn't enabled and driver would still compile, but it is guaranteed to fail as we don't continue when we get errors from regulator APIs.. Though I still feel that this driver should still support platforms without regulators (atleast in software, they might always have them on board :)).. And so dependencies for regulators may also die out one day.. The dependencies here mean: "This driver would never ever work/compile if the dependencies aren't met.." -- 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
Hi Viresh, On Fri, May 23, 2014 at 10:03:27AM +0530, Viresh Kumar wrote: > On 22 May 2014 20:22, Eduardo Valentin <edubezval@gmail.com> wrote: > > However, on CPUs that needs thermal managment, it makes sense to have > > such dependency, from functional perspective. Mainly because scaling > > frequency and voltage up would be allowed only when thermal management > > is enabled. > > AFAIK, dependencies in KCONFIG are only for fixing compilation time issues. Actually, they also impose module loading sequencing. > As some APIs wouldn't be available without enabling some config options.. > > If drivers fail at runtime because some API returned error, fix it for your > platform instead and not bug KCONFIG for that. Agreed, but I don't think this is the point of this thread, as you already stated in your patch description. > > Thought we might consider some runtime dependencies here as well. For > example regulators. There probably are dummy routine available for cases > where CONFIG_REGULATOR (or whatever) isn't enabled and driver would > still compile, but it is guaranteed to fail as we don't continue when we get > errors from regulator APIs.. I agree. We need to have runtime dependency, and that is the major concern on my behalf. The problem of Kconfig dependency is that it imposes sequencing only on module loading, not at boot sequencing. Another way around is returning -EPROBE_DEFER when some API is not ready at device probing for instance. > > Though I still feel that this driver should still support platforms without > regulators (atleast in software, they might always have them on board :)).. > And so dependencies for regulators may also die out one day.. > > The dependencies here mean: "This driver would never ever work/compile > if the dependencies aren't met.." -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
> On 23-May-2014, at 6:51 pm, Eduardo Valentin <edubezval@gmail.com> wrote: > I agree. We need to have runtime dependency, and that is the major > concern on my behalf. The problem of Kconfig dependency is that it > imposes sequencing only on module loading, not at boot sequencing. > > Another way around is returning -EPROBE_DEFER when some API is not ready at device probing for instance. Okay, coming back to this patch. This driver is usable without thermal. And so the dependencies better be dropped ?-- 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 Fri 2014-05-23 10:03:27, Viresh Kumar wrote: > On 22 May 2014 20:22, Eduardo Valentin <edubezval@gmail.com> wrote: > > However, on CPUs that needs thermal managment, it makes sense to have > > such dependency, from functional perspective. Mainly because scaling > > frequency and voltage up would be allowed only when thermal management > > is enabled. > > AFAIK, dependencies in KCONFIG are only for fixing compilation time issues. I do not think that's correct. -- 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 24 May 2014 18:29, Pavel Machek <pavel@ucw.cz> wrote: > On Fri 2014-05-23 10:03:27, Viresh Kumar wrote: >> On 22 May 2014 20:22, Eduardo Valentin <edubezval@gmail.com> wrote: >> > However, on CPUs that needs thermal managment, it makes sense to have >> > such dependency, from functional perspective. Mainly because scaling >> > frequency and voltage up would be allowed only when thermal management >> > is enabled. >> >> AFAIK, dependencies in KCONFIG are only for fixing compilation time issues. > > I do not think that's correct. Yeah, that what I accepted later as well.. Dependency is whatever without which the module is unusable. And cpufreq-cpu0 is usable without THERMAL and so this dependency should go away.. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
diff --git a/drivers/cpufreq/Kconfig b/drivers/cpufreq/Kconfig index 1fbe11f..4310997 100644 --- a/drivers/cpufreq/Kconfig +++ b/drivers/cpufreq/Kconfig @@ -185,7 +185,7 @@ config CPU_FREQ_GOV_CONSERVATIVE config GENERIC_CPUFREQ_CPU0 tristate "Generic CPU0 cpufreq driver" - depends on HAVE_CLK && REGULATOR && OF && THERMAL && CPU_THERMAL + depends on HAVE_CLK && REGULATOR && OF select PM_OPP help This adds a generic cpufreq driver for CPU0 frequency management.
cpufreq-cpu0 uses thermal framework to register a cooling device, but doesn't depend on it as there are dummy calls provided by thermal layer when CONFIG_THERMAL=n. So, we don't really need to mention thermal as a dependency for cpufreq-cpu0 in Kconfig. Remove it. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> --- drivers/cpufreq/Kconfig | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)