| Message ID | b4a56cad08c5ef701cf268881697caabe5229994.1416826729.git.viresh.kumar@linaro.org |
|---|---|
| State | New |
| Headers | show |
On 24 November 2014 at 23:40, Eduardo Valentin <edubezval@gmail.com> wrote: > Is it possible to have this registration only when we have a > cpufreq driver up and running? The reasoning is that only after we have > a way to control cpu frequencies, it makes sense to have the cpu_cooling > device. > > I am planing to have the following check in the cpu cooling code: > if (!cpufreq_get_current_driver()) { > dev_dbg(bgp->dev, "no cpufreq driver yet\n"); > return -EPROBE_DEFER; > } > > that is the way I think of checking if the cpufreq layer is ready to > have a cpu cooling on top of it. Currently, thermal drivers check this > before calling cpu cooling registration. But instead of having this > check in every driver, I would like to move it to cpu cooling. > > However, for cpufreq-dt, the registration currently happens in the > init phase, not in probe, so cpufreq driver is not registered, and thus > the check won't work. This is how the phases are present in cpufreq drivers: -> platform_init -> probe() ->cpufreq_driver->init() And the cooling device is registered in cpufreq_driver->init() and by the time ->init() is called, cpufreq_driver is valid. -- 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 25 November 2014 at 07:14, Eduardo Valentin <edubezval@gmail.com> wrote: > You are right! I got confused because even with your patch, the > sequencing is not working. Looking to that behavior I, somehow, thought > the _init function in cpufreq-dt was about init() calls. But in fact, it > is driver initialization callback. :) > However, by the time of ->init() the cpufreq_driver is not really ready. I agree. > Or at least, the cpufreq layer is not ready. A call to > > cpufreq_frequency_get_table() > > for instance, it is not working. I know the story you pasted here :) > The cpufreq-dt would need to add the of based cpufreq cooling only when > cpufreq layer is ready. Any other better cpufreq driver callback to add > the cpu cooling? There is nothing as of now atleast. > We could sort this out by polling in thermal layer for the cpufreq table > until it gets ready, but I believe that would be a dirty hack. Yeah. Probably we can add a notifier for cpufreq-driver addition/removal. That's the best we can do I believe. -- 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 26 November 2014 at 02:17, Rafael J. Wysocki <rjw@rjwysocki.net> wrote: > Can we please avoid adding any new notifiers? Sure :) > We can add a new cpufreq driver callback to be invoked by the core when > everything has been set up for this purpose. Hmm, that will be better.. -- 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 26 November 2014 at 03:19, Rafael J. Wysocki <rjw@rjwysocki.net> wrote:
> Plus "stable" I suppose? Which ones?
I haven't put stable tags intentionally as the driver was updated/renamed in
3.18 and whatever patch we produce wouldn't get applied to any stable.
So, if we want to fix this problem in 'stable' then we have to write another
similar patch..
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On 26 November 2014 at 03:35, Rafael J. Wysocki <rjw@rjwysocki.net> wrote:
> And what bad things are going to happen if this is not pushed for 3.18?
This is what Eduardo reported in one of the mails:
---
As an example, I am taking the ti-soc-thermal, but we already have other
of-thermal based drivers. Booting with this patch ti-soc-thermal
(of-based boot) loads fine, but the cpu_cooling never gets bound to the
thermal zone.
The thing is that the bind may happen before cpufreq-dt code loads the
cpufreq driver, and when cpu_cooling is checking what is the max freq,
by using cpufreq table, it won't be able to do it, as there is no table.
While, without the patch, it will use wrong in the binding, but after
it gets bound, and cpufreq loads, the max will be used correctly.
----
And so it looked like things aren't going to work smoothly in 3.18
and so I thought we should get it in.
But probably the problem will be worst only after applying Lukasz
patchset?
@Eduardo: Do you want Rafael to apply this for 3.18? or 3.19 will
work as well ?
--
viresh
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On 26 November 2014 at 11:27, Viresh Kumar <viresh.kumar@linaro.org> wrote: > On 26 November 2014 at 03:35, Rafael J. Wysocki <rjw@rjwysocki.net> wrote: >> And what bad things are going to happen if this is not pushed for 3.18? > > This is what Eduardo reported in one of the mails: https://lkml.org/lkml/2014/11/21/451 -- 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/drivers/cpufreq/cpufreq-dt.c b/drivers/cpufreq/cpufreq-dt.c index 8cba13d..22eb6e5 100644 --- a/drivers/cpufreq/cpufreq-dt.c +++ b/drivers/cpufreq/cpufreq-dt.c @@ -186,7 +186,6 @@ 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; @@ -269,20 +268,6 @@ 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; @@ -292,7 +277,22 @@ 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 out_free_cpufreq_table; + } + + /* + * For now, just loading the cooling device; + * thermal DT code takes care of matching them. + */ + if (of_find_property(np, "#cooling-cells", NULL)) { + priv->cdev = of_cpufreq_cooling_register(np, cpu_present_mask); + if (IS_ERR(priv->cdev)) { + dev_err(cpu_dev, + "running cpufreq without cooling device: %ld\n", + PTR_ERR(priv->cdev)); + + priv->cdev = NULL; + } } policy->cpuinfo.transition_latency = transition_latency; @@ -305,8 +305,7 @@ static int cpufreq_init(struct cpufreq_policy *policy) return 0; -out_cooling_unregister: - cpufreq_cooling_unregister(priv->cdev); +out_free_cpufreq_table: dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table); out_free_priv: kfree(priv);
of_cpufreq_cooling_register() can use frequency values from policy->min/max/cpuinfo.min_freq/cpuinfo.max_freq, which are available only after calling cpufreq_table_validate_and_show(). The right order of calling should be: cpufreq_table_validate_and_show() followed by of_cpufreq_cooling_register(). Fix it. Reported-by: Lukasz Majewski <l.majewski@samsung.com> Reported-by: Eduardo Valentin <edubezval@gmail.com> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> --- For 3.18. --- drivers/cpufreq/cpufreq-dt.c | 35 +++++++++++++++++------------------ 1 file changed, 17 insertions(+), 18 deletions(-)