From: Mikko Perttunen <[email protected]>
Thermal zones located in power domains may not be accessible when
the domain is powergated. In this situation, reading the temperature
will return -BPMP_EFAULT. When evaluating trips, BPMP will internally
use -256C as the temperature for offline zones.
For smooth operation, for offline zones, return -EAGAIN when reading
the temperature and allow registration of zones even if they are
offline during probe.
Signed-off-by: Mikko Perttunen <[email protected]>
---
v2:
* Adjusted commit message.
* Patch 2/2 dropped for now since it is more controversial,
and this patch is more critical.
drivers/thermal/tegra/tegra-bpmp-thermal.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/drivers/thermal/tegra/tegra-bpmp-thermal.c b/drivers/thermal/tegra/tegra-bpmp-thermal.c
index f5fd4018f72f..4ffc3bb3bf35 100644
--- a/drivers/thermal/tegra/tegra-bpmp-thermal.c
+++ b/drivers/thermal/tegra/tegra-bpmp-thermal.c
@@ -52,6 +52,8 @@ static int __tegra_bpmp_thermal_get_temp(struct tegra_bpmp_thermal_zone *zone,
err = tegra_bpmp_transfer(zone->tegra->bpmp, &msg);
if (err)
return err;
+ if (msg.rx.ret == -BPMP_EFAULT)
+ return -EAGAIN;
if (msg.rx.ret)
return -EINVAL;
@@ -259,7 +261,12 @@ static int tegra_bpmp_thermal_probe(struct platform_device *pdev)
zone->tegra = tegra;
err = __tegra_bpmp_thermal_get_temp(zone, &temp);
- if (err < 0) {
+
+ /*
+ * Sensors in powergated domains may temporarily fail to be read
+ * (-EAGAIN), but will become accessible when the domain is powered on.
+ */
+ if (err < 0 && err != -EAGAIN) {
devm_kfree(&pdev->dev, zone);
continue;
}
--
2.39.2
On 30/03/2023 11:49, Mikko Perttunen wrote:
> From: Mikko Perttunen <[email protected]>
>
> Thermal zones located in power domains may not be accessible when
> the domain is powergated. In this situation, reading the temperature
> will return -BPMP_EFAULT. When evaluating trips, BPMP will internally
> use -256C as the temperature for offline zones.
> For smooth operation, for offline zones, return -EAGAIN when reading
> the temperature and allow registration of zones even if they are
> offline during probe.
I think it makes more sense to check if the power domain associated with
the device is powered up and if not return -EPROBE_DEFER.
> Signed-off-by: Mikko Perttunen <[email protected]>
> ---
> v2:
> * Adjusted commit message.
> * Patch 2/2 dropped for now since it is more controversial,
> and this patch is more critical.
>
> drivers/thermal/tegra/tegra-bpmp-thermal.c | 9 ++++++++-
> 1 file changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/thermal/tegra/tegra-bpmp-thermal.c b/drivers/thermal/tegra/tegra-bpmp-thermal.c
> index f5fd4018f72f..4ffc3bb3bf35 100644
> --- a/drivers/thermal/tegra/tegra-bpmp-thermal.c
> +++ b/drivers/thermal/tegra/tegra-bpmp-thermal.c
> @@ -52,6 +52,8 @@ static int __tegra_bpmp_thermal_get_temp(struct tegra_bpmp_thermal_zone *zone,
> err = tegra_bpmp_transfer(zone->tegra->bpmp, &msg);
> if (err)
> return err;
> + if (msg.rx.ret == -BPMP_EFAULT)
> + return -EAGAIN;
> if (msg.rx.ret)
> return -EINVAL;
>
> @@ -259,7 +261,12 @@ static int tegra_bpmp_thermal_probe(struct platform_device *pdev)
> zone->tegra = tegra;
>
> err = __tegra_bpmp_thermal_get_temp(zone, &temp);
> - if (err < 0) {
> +
> + /*
> + * Sensors in powergated domains may temporarily fail to be read
> + * (-EAGAIN), but will become accessible when the domain is powered on.
> + */
> + if (err < 0 && err != -EAGAIN) {
> devm_kfree(&pdev->dev, zone);
> continue;
> }
--
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On 3/30/23 13:03, Daniel Lezcano wrote:
> On 30/03/2023 11:49, Mikko Perttunen wrote:
>> From: Mikko Perttunen <[email protected]>
>>
>> Thermal zones located in power domains may not be accessible when
>> the domain is powergated. In this situation, reading the temperature
>> will return -BPMP_EFAULT. When evaluating trips, BPMP will internally
>> use -256C as the temperature for offline zones.
>
>> For smooth operation, for offline zones, return -EAGAIN when reading
>> the temperature and allow registration of zones even if they are
>> offline during probe.
>
> I think it makes more sense to check if the power domain associated with
> the device is powered up and if not return -EPROBE_DEFER.
The power domains in question are related to computer vision engines
that only get powered on when in use, possibly never if the user doesn't
run a computer vision workload on the system. We still want other
thermal zones to be available.
Mikko
>
>
>> Signed-off-by: Mikko Perttunen <[email protected]>
>> ---
>> v2:
>> * Adjusted commit message.
>> * Patch 2/2 dropped for now since it is more controversial,
>> and this patch is more critical.
>>
>> drivers/thermal/tegra/tegra-bpmp-thermal.c | 9 ++++++++-
>> 1 file changed, 8 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/thermal/tegra/tegra-bpmp-thermal.c
>> b/drivers/thermal/tegra/tegra-bpmp-thermal.c
>> index f5fd4018f72f..4ffc3bb3bf35 100644
>> --- a/drivers/thermal/tegra/tegra-bpmp-thermal.c
>> +++ b/drivers/thermal/tegra/tegra-bpmp-thermal.c
>> @@ -52,6 +52,8 @@ static int __tegra_bpmp_thermal_get_temp(struct
>> tegra_bpmp_thermal_zone *zone,
>> err = tegra_bpmp_transfer(zone->tegra->bpmp, &msg);
>> if (err)
>> return err;
>> + if (msg.rx.ret == -BPMP_EFAULT)
>> + return -EAGAIN;
>> if (msg.rx.ret)
>> return -EINVAL;
>> @@ -259,7 +261,12 @@ static int tegra_bpmp_thermal_probe(struct
>> platform_device *pdev)
>> zone->tegra = tegra;
>> err = __tegra_bpmp_thermal_get_temp(zone, &temp);
>> - if (err < 0) {
>> +
>> + /*
>> + * Sensors in powergated domains may temporarily fail to be read
>> + * (-EAGAIN), but will become accessible when the domain is
>> powered on.
>> + */
>> + if (err < 0 && err != -EAGAIN) {
>> devm_kfree(&pdev->dev, zone);
>> continue;
>> }
>
On 30/03/2023 12:06, Mikko Perttunen wrote:
> On 3/30/23 13:03, Daniel Lezcano wrote:
>> On 30/03/2023 11:49, Mikko Perttunen wrote:
>>> From: Mikko Perttunen <[email protected]>
>>>
>>> Thermal zones located in power domains may not be accessible when
>>> the domain is powergated. In this situation, reading the temperature
>>> will return -BPMP_EFAULT. When evaluating trips, BPMP will internally
>>> use -256C as the temperature for offline zones.
>>
>>> For smooth operation, for offline zones, return -EAGAIN when reading
>>> the temperature and allow registration of zones even if they are
>>> offline during probe.
>>
>> I think it makes more sense to check if the power domain associated
>> with the device is powered up and if not return -EPROBE_DEFER.
>
> The power domains in question are related to computer vision engines
> that only get powered on when in use, possibly never if the user doesn't
> run a computer vision workload on the system. We still want other
> thermal zones to be available.
Ok, I see the point.
I'm worried about the semantic of the errors returned, the translation
from BPMP_EFAULT to EAGAIN and the assumption it is a disabled (may be
forever) thermal zone.
What does the documentation say for the error msg.rx.ret == -BPMP_EFAULT?
>>> Signed-off-by: Mikko Perttunen <[email protected]>
>>> ---
>>> v2:
>>> * Adjusted commit message.
>>> * Patch 2/2 dropped for now since it is more controversial,
>>> and this patch is more critical.
>>>
>>> drivers/thermal/tegra/tegra-bpmp-thermal.c | 9 ++++++++-
>>> 1 file changed, 8 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/thermal/tegra/tegra-bpmp-thermal.c
>>> b/drivers/thermal/tegra/tegra-bpmp-thermal.c
>>> index f5fd4018f72f..4ffc3bb3bf35 100644
>>> --- a/drivers/thermal/tegra/tegra-bpmp-thermal.c
>>> +++ b/drivers/thermal/tegra/tegra-bpmp-thermal.c
>>> @@ -52,6 +52,8 @@ static int __tegra_bpmp_thermal_get_temp(struct
>>> tegra_bpmp_thermal_zone *zone,
>>> err = tegra_bpmp_transfer(zone->tegra->bpmp, &msg);
>>> if (err)
>>> return err;
>>> + if (msg.rx.ret == -BPMP_EFAULT)
>>> + return -EAGAIN;
>>> if (msg.rx.ret)
>>> return -EINVAL;
>>> @@ -259,7 +261,12 @@ static int tegra_bpmp_thermal_probe(struct
>>> platform_device *pdev)
>>> zone->tegra = tegra;
>>> err = __tegra_bpmp_thermal_get_temp(zone, &temp);
>>> - if (err < 0) {
>>> +
>>> + /*
>>> + * Sensors in powergated domains may temporarily fail to be
>>> read
>>> + * (-EAGAIN), but will become accessible when the domain is
>>> powered on.
>>> + */
>>> + if (err < 0 && err != -EAGAIN) {
>>> devm_kfree(&pdev->dev, zone);
>>> continue;
>>> }
>>
>
--
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Follow Linaro: <http://www.facebook.com/pages/Linaro> Facebook |
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On 3/30/23 15:36, Daniel Lezcano wrote:
> On 30/03/2023 12:06, Mikko Perttunen wrote:
>> On 3/30/23 13:03, Daniel Lezcano wrote:
>>> On 30/03/2023 11:49, Mikko Perttunen wrote:
>>>> From: Mikko Perttunen <[email protected]>
>>>>
>>>> Thermal zones located in power domains may not be accessible when
>>>> the domain is powergated. In this situation, reading the temperature
>>>> will return -BPMP_EFAULT. When evaluating trips, BPMP will internally
>>>> use -256C as the temperature for offline zones.
>>>
>>>> For smooth operation, for offline zones, return -EAGAIN when reading
>>>> the temperature and allow registration of zones even if they are
>>>> offline during probe.
>>>
>>> I think it makes more sense to check if the power domain associated
>>> with the device is powered up and if not return -EPROBE_DEFER.
>>
>> The power domains in question are related to computer vision engines
>> that only get powered on when in use, possibly never if the user
>> doesn't run a computer vision workload on the system. We still want
>> other thermal zones to be available.
>
> Ok, I see the point.
>
> I'm worried about the semantic of the errors returned, the translation
> from BPMP_EFAULT to EAGAIN and the assumption it is a disabled (may be
> forever) thermal zone.
>
> What does the documentation say for the error msg.rx.ret == -BPMP_EFAULT?
>
The documentation says
Value | Description
-------------- | -----------------------------------------
0 | Temperature query succeeded.
-#BPMP_EINVAL | Invalid request parameters.
-#BPMP_ENOENT | No driver registered for thermal zone.
-#BPMP_EFAULT | Problem reading temperature measurement.
In practice, what BPMP_EFAULT means here is that the hardware has no
indicated temperature for the zone, which really only happens if the
power domain is powered off.
Mikko
>
>>>> Signed-off-by: Mikko Perttunen <[email protected]>
>>>> ---
>>>> v2:
>>>> * Adjusted commit message.
>>>> * Patch 2/2 dropped for now since it is more controversial,
>>>> and this patch is more critical.
>>>>
>>>> drivers/thermal/tegra/tegra-bpmp-thermal.c | 9 ++++++++-
>>>> 1 file changed, 8 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/drivers/thermal/tegra/tegra-bpmp-thermal.c
>>>> b/drivers/thermal/tegra/tegra-bpmp-thermal.c
>>>> index f5fd4018f72f..4ffc3bb3bf35 100644
>>>> --- a/drivers/thermal/tegra/tegra-bpmp-thermal.c
>>>> +++ b/drivers/thermal/tegra/tegra-bpmp-thermal.c
>>>> @@ -52,6 +52,8 @@ static int __tegra_bpmp_thermal_get_temp(struct
>>>> tegra_bpmp_thermal_zone *zone,
>>>> err = tegra_bpmp_transfer(zone->tegra->bpmp, &msg);
>>>> if (err)
>>>> return err;
>>>> + if (msg.rx.ret == -BPMP_EFAULT)
>>>> + return -EAGAIN;
>>>> if (msg.rx.ret)
>>>> return -EINVAL;
>>>> @@ -259,7 +261,12 @@ static int tegra_bpmp_thermal_probe(struct
>>>> platform_device *pdev)
>>>> zone->tegra = tegra;
>>>> err = __tegra_bpmp_thermal_get_temp(zone, &temp);
>>>> - if (err < 0) {
>>>> +
>>>> + /*
>>>> + * Sensors in powergated domains may temporarily fail to be
>>>> read
>>>> + * (-EAGAIN), but will become accessible when the domain is
>>>> powered on.
>>>> + */
>>>> + if (err < 0 && err != -EAGAIN) {
>>>> devm_kfree(&pdev->dev, zone);
>>>> continue;
>>>> }
>>>
>>
>
On Thu, Mar 30, 2023 at 12:49:04PM +0300, Mikko Perttunen wrote:
> From: Mikko Perttunen <[email protected]>
>
> Thermal zones located in power domains may not be accessible when
> the domain is powergated. In this situation, reading the temperature
> will return -BPMP_EFAULT. When evaluating trips, BPMP will internally
> use -256C as the temperature for offline zones.
>
> For smooth operation, for offline zones, return -EAGAIN when reading
> the temperature and allow registration of zones even if they are
> offline during probe.
>
> Signed-off-by: Mikko Perttunen <[email protected]>
> ---
> v2:
> * Adjusted commit message.
> * Patch 2/2 dropped for now since it is more controversial,
> and this patch is more critical.
>
> drivers/thermal/tegra/tegra-bpmp-thermal.c | 9 ++++++++-
> 1 file changed, 8 insertions(+), 1 deletion(-)
Acked-by: Thierry Reding <[email protected]>
On 30/03/2023 11:49, Mikko Perttunen wrote:
> From: Mikko Perttunen <[email protected]>
>
> Thermal zones located in power domains may not be accessible when
> the domain is powergated. In this situation, reading the temperature
> will return -BPMP_EFAULT. When evaluating trips, BPMP will internally
> use -256C as the temperature for offline zones.
>
> For smooth operation, for offline zones, return -EAGAIN when reading
> the temperature and allow registration of zones even if they are
> offline during probe.
>
> Signed-off-by: Mikko Perttunen <[email protected]>
Applied, thanks
--
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On 3/31/23 00:14, Daniel Lezcano wrote:
> On 30/03/2023 11:49, Mikko Perttunen wrote:
>> From: Mikko Perttunen <[email protected]>
>>
>> Thermal zones located in power domains may not be accessible when
>> the domain is powergated. In this situation, reading the temperature
>> will return -BPMP_EFAULT. When evaluating trips, BPMP will internally
>> use -256C as the temperature for offline zones.
>>
>> For smooth operation, for offline zones, return -EAGAIN when reading
>> the temperature and allow registration of zones even if they are
>> offline during probe.
>>
>> Signed-off-by: Mikko Perttunen <[email protected]>
>
> Applied, thanks
>
Thank you!
Mikko