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(-)
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);
Viresh
On Mon, Nov 24, 2014 at 04:29:13PM +0530, Viresh Kumar wrote:
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(-)
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));elsepriv->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;}
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.
In this way, I believe the sequencing between cpu cooling and cpufreq-dt would work fine.
} 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); -- 2.0.3.693.g996b0fd
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.
Viresh,
On Tue, Nov 25, 2014 at 04:27:44PM +0530, Viresh Kumar wrote:
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()
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.
And the cooling device is registered in cpufreq_driver->init() and by the time ->init() is called, cpufreq_driver is valid.
However, by the time of ->init() the cpufreq_driver is not really ready. Or at least, the cpufreq layer is not ready. A call to
cpufreq_frequency_get_table()
for instance, it is not working. The reasoning is because cpufreq_add_dev() is still not finalized by the time driver->init() is called. Meaning, the policy cannot be fetch because the cpu masks have not been set by that time. More important, in order to fetch the cpufreq table we would need to have the cpufreq_cpu_data properly initialized per cpu. In other words, when we call driver->init() that happens before the following code: cpumask_and(policy->cpus, policy->cpus, cpu_online_mask);
if (!recover_policy) { policy->user_policy.min = policy->min; policy->user_policy.max = policy->max; }
down_write(&policy->rwsem); write_lock_irqsave(&cpufreq_driver_lock, flags); for_each_cpu(j, policy->cpus) per_cpu(cpufreq_cpu_data, j) = policy; write_unlock_irqrestore(&cpufreq_driver_lock, flags);
The thing is, with current code: cpufreq_add_dev() -> cpufreq-dt->init() -> of_cpufreq_cooling_register() -> cpufreq_frequency_get_table() -> returns NULL;
Returns invalid data because it is not initialized yet.
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?
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.
Cheers,
Eduardo Valentin
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.
On Tuesday, November 25, 2014 08:56:00 PM Viresh Kumar wrote:
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.
Can we please avoid adding any new notifiers?
We can add a new cpufreq driver callback to be invoked by the core when everything has been set up for this purpose.
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..
Hi Viresh,
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(-)
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 coolingdevice: %ld\n",
PTR_ERR(cdev));elsepriv->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 coolingdevice: %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);
Reviewed-by: Lukasz Majewski l.majewski@samsung.com
On Monday, November 24, 2014 04:29:13 PM Viresh Kumar wrote:
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.
Plus "stable" I suppose? Which ones?
drivers/cpufreq/cpufreq-dt.c | 35 +++++++++++++++++------------------ 1 file changed, 17 insertions(+), 18 deletions(-)
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));elsepriv->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);
On Tuesday, November 25, 2014 10:49:32 PM Rafael J. Wysocki wrote:
On Monday, November 24, 2014 04:29:13 PM Viresh Kumar wrote:
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.
Plus "stable" I suppose? Which ones?
And what bad things are going to happen if this is not pushed for 3.18?
drivers/cpufreq/cpufreq-dt.c | 35 +++++++++++++++++------------------ 1 file changed, 17 insertions(+), 18 deletions(-)
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));elsepriv->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);
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
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:
Hello Viresh, Rafael,
On Wed, Nov 26, 2014 at 11:27:42AM +0530, Viresh Kumar 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:
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.
The bug exists, it is there for 3.18. But also, as I explained in that thread, the current code is able to initialize the of cooling device and to register it in its thermal zone. But that works by lucky because we do not have the proper return code checks in thermal core.
But probably the problem will be worst only after applying Lukasz patchset?
The bug gets exposed by his patch.
@Eduardo: Do you want Rafael to apply this for 3.18? or 3.19 will work as well ?
I believe, for this case, 3.19 is best option. Looks like we have a possible API massage coming, so, targetting 3.18 would be rushy. I'd rather think of a proper way to fix this, scalable and that makes sense to everybody, even if takes extra merge window, than rushing for a fix that we may need to revisit it again in near future.
BR,
Eduardo Valentin
-- viresh
On Wednesday, November 26, 2014 11:10:32 AM Eduardo Valentin wrote:
--T4sUOijqQbZv57TR Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable
Hello Viresh, Rafael,
On Wed, Nov 26, 2014 at 11:27:42AM +0530, Viresh Kumar 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?
=20 This is what Eduardo reported in one of the mails: =20
=20 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. =20 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. =20 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. =20
=20 And so it looked like things aren't going to work smoothly in 3.18 and so I thought we should get it in. =20
The bug exists, it is there for 3.18. But also, as I explained in that thread, the current code is able to initialize the of cooling device and to register it in its thermal zone. But that works by lucky because we do not have the proper return code checks in thermal core.
But probably the problem will be worst only after applying Lukasz patchset?
The bug gets exposed by his patch.
=20 @Eduardo: Do you want Rafael to apply this for 3.18? or 3.19 will work as well ?
I believe, for this case, 3.19 is best option. Looks like we have a possible API massage coming, so, targetting 3.18 would be rushy. I'd rather think of a proper way to fix this, scalable and that makes sense to everybody, even if takes extra merge window, than rushing for a fix that we may need to revisit it again in near future.
That's my view as well.
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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