[PATCH] PM / Domains: Return -EPROBE_DEFER if we fail to init or turn-on domain

[PATCH] PM / Domains: Return -EPROBE_DEFER if we fail to init or turn-on domain

[Jon Hunter]

When a device is probed, the function dev_pm_domain_attach() is called
to see if there is a power-domain that is associated with the device and
needs to be turned on. If dev_pm_domain_attach() does not return
-EPROBE_DEFER then the device will be probed.

For devices using genpd, dev_pm_domain_attach() will call
genpd_dev_pm_attach(). If genpd_dev_pm_attach() does not find a power
domain associated with the device then it returns an error code not
equal to -EPROBE_DEFER to allow the device to be probed. However, if
genpd_dev_pm_attach() does find a power-domain that is associated with
the device, then it does not return -EPROBE_DEFER on failure and hence
the device will still be probed. Furthermore, genpd_dev_pm_attach() does
not check the error code returned by pm_genpd_poweron() to see if the
power-domain was turned on successfully.

Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Acked-by: Ulf Hansson <ulf.hansson@linaro.org>
---
 drivers/base/power/domain.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index a1abe16dfe16..7666a1cbaf95 100644
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -1947,7 +1947,10 @@ static void genpd_dev_pm_sync(struct device *dev)
  * Both generic and legacy Samsung-specific DT bindings are supported to keep
  * backwards compatibility with existing DTBs.
  *
- * Returns 0 on successfully attached PM domain or negative error code.
+ * Returns 0 on successfully attached PM domain or negative error code. Note
+ * that if a power-domain exists for the device, but it cannot be found or
+ * turned on, then return -EPROBE_DEFER to ensure that the device is not
+ * probed and to re-try again later.
  */
 int genpd_dev_pm_attach(struct device *dev)
 {
@@ -1984,7 +1987,7 @@ int genpd_dev_pm_attach(struct device *dev)
 		dev_dbg(dev, "%s() failed to find PM domain: %ld\n",
 			__func__, PTR_ERR(pd));
 		of_node_put(dev->of_node);
-		return PTR_ERR(pd);
+		return -EPROBE_DEFER;
 	}
 
 	dev_dbg(dev, "adding to PM domain %s\n", pd->name);
@@ -2002,14 +2005,15 @@ int genpd_dev_pm_attach(struct device *dev)
 		dev_err(dev, "failed to add to PM domain %s: %d",
 			pd->name, ret);
 		of_node_put(dev->of_node);
-		return ret;
+		goto out;
 	}
 
 	dev->pm_domain->detach = genpd_dev_pm_detach;
 	dev->pm_domain->sync = genpd_dev_pm_sync;
-	pm_genpd_poweron(pd);
+	ret = pm_genpd_poweron(pd);
 
-	return 0;
+out:
+	return ret ? -EPROBE_DEFER : 0;
 }
 EXPORT_SYMBOL_GPL(genpd_dev_pm_attach);
 #endif /* CONFIG_PM_GENERIC_DOMAINS_OF */
-- 
2.1.4

Re: [PATCH] PM / Domains: Return -EPROBE_DEFER if we fail to init or turn-on domain

[Kevin Hilman]

[ sorry for the lag, been on vacation... ]

Hi Jon,

Jon Hunter <jonathanh@nvidia.com> writes:

> When a device is probed, the function dev_pm_domain_attach() is called
> to see if there is a power-domain that is associated with the device and
> needs to be turned on. If dev_pm_domain_attach() does not return
> -EPROBE_DEFER then the device will be probed.
>
> For devices using genpd, dev_pm_domain_attach() will call
> genpd_dev_pm_attach(). If genpd_dev_pm_attach() does not find a power
> domain associated with the device then it returns an error code not
> equal to -EPROBE_DEFER to allow the device to be probed. However, if
> genpd_dev_pm_attach() does find a power-domain that is associated with
> the device, then it does not return -EPROBE_DEFER on failure and hence
> the device will still be probed. Furthermore, genpd_dev_pm_attach() does
> not check the error code returned by pm_genpd_poweron() to see if the
> power-domain was turned on successfully.

That's a good description of the problem, but doesn't describe the fix
the fix.

Please summarize the solution being implemented here...

> Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
> Acked-by: Ulf Hansson <ulf.hansson@linaro.org>

... otherwise, patch itself looks fine.  Feel free to add

Acked-by: Kevin Hilman <khilman@linaro.org>

[PATCH] PM / Domains: Return -EPROBE_DEFER if we fail to init or turn-on domain

[Jon Hunter]

When a device is probed, the function dev_pm_domain_attach() is called
to see if there is a power-domain that is associated with the device and
needs to be turned on. If dev_pm_domain_attach() does not return
-EPROBE_DEFER then the device will be probed.

For devices using genpd, dev_pm_domain_attach() will call
genpd_dev_pm_attach(). If genpd_dev_pm_attach() does not find a power
domain associated with the device then it returns an error code not
equal to -EPROBE_DEFER to allow the device to be probed. However, if
genpd_dev_pm_attach() does find a power-domain that is associated with
the device, then it does not return -EPROBE_DEFER on failure and hence
the device will still be probed. Furthermore, genpd_dev_pm_attach() does
not check the error code returned by pm_genpd_poweron() to see if the
power-domain was turned on successfully.

Fix this by checking the return code from pm_genpd_poweron() and
returning -EPROBE_DEFER from genpd_dev_pm_attach on failure, if there
is a power-domain associated with the device.

Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Acked-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Kevin Hilman <khilman@linaro.org>
---
 drivers/base/power/domain.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index a1abe16dfe16..7666a1cbaf95 100644
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -1947,7 +1947,10 @@ static void genpd_dev_pm_sync(struct device *dev)
  * Both generic and legacy Samsung-specific DT bindings are supported to keep
  * backwards compatibility with existing DTBs.
  *
- * Returns 0 on successfully attached PM domain or negative error code.
+ * Returns 0 on successfully attached PM domain or negative error code. Note
+ * that if a power-domain exists for the device, but it cannot be found or
+ * turned on, then return -EPROBE_DEFER to ensure that the device is not
+ * probed and to re-try again later.
  */
 int genpd_dev_pm_attach(struct device *dev)
 {
@@ -1984,7 +1987,7 @@ int genpd_dev_pm_attach(struct device *dev)
 		dev_dbg(dev, "%s() failed to find PM domain: %ld\n",
 			__func__, PTR_ERR(pd));
 		of_node_put(dev->of_node);
-		return PTR_ERR(pd);
+		return -EPROBE_DEFER;
 	}
 
 	dev_dbg(dev, "adding to PM domain %s\n", pd->name);
@@ -2002,14 +2005,15 @@ int genpd_dev_pm_attach(struct device *dev)
 		dev_err(dev, "failed to add to PM domain %s: %d",
 			pd->name, ret);
 		of_node_put(dev->of_node);
-		return ret;
+		goto out;
 	}
 
 	dev->pm_domain->detach = genpd_dev_pm_detach;
 	dev->pm_domain->sync = genpd_dev_pm_sync;
-	pm_genpd_poweron(pd);
+	ret = pm_genpd_poweron(pd);
 
-	return 0;
+out:
+	return ret ? -EPROBE_DEFER : 0;
 }
 EXPORT_SYMBOL_GPL(genpd_dev_pm_attach);
 #endif /* CONFIG_PM_GENERIC_DOMAINS_OF */
-- 
2.1.4

Re: [PATCH] PM / Domains: Return -EPROBE_DEFER if we fail to init or turn-on domain

[Jon Hunter]

Ugh ... forgot to mark this as a V2! Will resend for clarity ...

On 31/07/15 10:16, Jon Hunter wrote:
> When a device is probed, the function dev_pm_domain_attach() is called
> to see if there is a power-domain that is associated with the device and
> needs to be turned on. If dev_pm_domain_attach() does not return
> -EPROBE_DEFER then the device will be probed.
> 
> For devices using genpd, dev_pm_domain_attach() will call
> genpd_dev_pm_attach(). If genpd_dev_pm_attach() does not find a power
> domain associated with the device then it returns an error code not
> equal to -EPROBE_DEFER to allow the device to be probed. However, if
> genpd_dev_pm_attach() does find a power-domain that is associated with
> the device, then it does not return -EPROBE_DEFER on failure and hence
> the device will still be probed. Furthermore, genpd_dev_pm_attach() does
> not check the error code returned by pm_genpd_poweron() to see if the
> power-domain was turned on successfully.
> 
> Fix this by checking the return code from pm_genpd_poweron() and
> returning -EPROBE_DEFER from genpd_dev_pm_attach on failure, if there
> is a power-domain associated with the device.
> 
> Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
> Acked-by: Ulf Hansson <ulf.hansson@linaro.org>
> Acked-by: Kevin Hilman <khilman@linaro.org>
> ---
>  drivers/base/power/domain.c | 14 +++++++++-----
>  1 file changed, 9 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
> index a1abe16dfe16..7666a1cbaf95 100644
> --- a/drivers/base/power/domain.c
> +++ b/drivers/base/power/domain.c
> @@ -1947,7 +1947,10 @@ static void genpd_dev_pm_sync(struct device *dev)
>   * Both generic and legacy Samsung-specific DT bindings are supported to keep
>   * backwards compatibility with existing DTBs.
>   *
> - * Returns 0 on successfully attached PM domain or negative error code.
> + * Returns 0 on successfully attached PM domain or negative error code. Note
> + * that if a power-domain exists for the device, but it cannot be found or
> + * turned on, then return -EPROBE_DEFER to ensure that the device is not
> + * probed and to re-try again later.
>   */
>  int genpd_dev_pm_attach(struct device *dev)
>  {
> @@ -1984,7 +1987,7 @@ int genpd_dev_pm_attach(struct device *dev)
>  		dev_dbg(dev, "%s() failed to find PM domain: %ld\n",
>  			__func__, PTR_ERR(pd));
>  		of_node_put(dev->of_node);
> -		return PTR_ERR(pd);
> +		return -EPROBE_DEFER;
>  	}
>  
>  	dev_dbg(dev, "adding to PM domain %s\n", pd->name);
> @@ -2002,14 +2005,15 @@ int genpd_dev_pm_attach(struct device *dev)
>  		dev_err(dev, "failed to add to PM domain %s: %d",
>  			pd->name, ret);
>  		of_node_put(dev->of_node);
> -		return ret;
> +		goto out;
>  	}
>  
>  	dev->pm_domain->detach = genpd_dev_pm_detach;
>  	dev->pm_domain->sync = genpd_dev_pm_sync;
> -	pm_genpd_poweron(pd);
> +	ret = pm_genpd_poweron(pd);
>  
> -	return 0;
> +out:
> +	return ret ? -EPROBE_DEFER : 0;
>  }
>  EXPORT_SYMBOL_GPL(genpd_dev_pm_attach);
>  #endif /* CONFIG_PM_GENERIC_DOMAINS_OF */
> 

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Re: [PATCH] PM / Domains: Return -EPROBE_DEFER if we fail to init or turn-on domain

[Jon Hunter]

On 31/07/15 00:28, Kevin Hilman wrote:
> [ sorry for the lag, been on vacation... ]
> 
> Hi Jon,
> 
> Jon Hunter <jonathanh@nvidia.com> writes:
> 
>> When a device is probed, the function dev_pm_domain_attach() is called
>> to see if there is a power-domain that is associated with the device and
>> needs to be turned on. If dev_pm_domain_attach() does not return
>> -EPROBE_DEFER then the device will be probed.
>>
>> For devices using genpd, dev_pm_domain_attach() will call
>> genpd_dev_pm_attach(). If genpd_dev_pm_attach() does not find a power
>> domain associated with the device then it returns an error code not
>> equal to -EPROBE_DEFER to allow the device to be probed. However, if
>> genpd_dev_pm_attach() does find a power-domain that is associated with
>> the device, then it does not return -EPROBE_DEFER on failure and hence
>> the device will still be probed. Furthermore, genpd_dev_pm_attach() does
>> not check the error code returned by pm_genpd_poweron() to see if the
>> power-domain was turned on successfully.
> 
> That's a good description of the problem, but doesn't describe the fix
> the fix.
> 
> Please summarize the solution being implemented here...

Ok, np.

>> Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
>> Acked-by: Ulf Hansson <ulf.hansson@linaro.org>
> 
> ... otherwise, patch itself looks fine.  Feel free to add
> 
> Acked-by: Kevin Hilman <khilman@linaro.org>

Thanks. I just send out an updated version.

Cheers Jon

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This email message is for the sole use of the intended recipient(s) and may contain
confidential information.  Any unauthorized review, use, disclosure or distribution
is prohibited.  If you are not the intended recipient, please contact the sender by
reply email and destroy all copies of the original message.
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