Messages in this thread | | | From | Ulf Hansson <> | Date | Thu, 17 Aug 2023 23:40:33 +0200 | Subject | Re: [PATCH 1/1] thermal/drivers/imx_sc_thermal: return -EAGAIN when SCFW turn off resource |
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On Thu, 17 Aug 2023 at 17:31, Frank Li <Frank.li@nxp.com> wrote: > > On Wed, Aug 16, 2023 at 11:23:17PM +0200, Ulf Hansson wrote: > > On Wed, 16 Aug 2023 at 22:46, Daniel Lezcano <daniel.lezcano@linaro.org> wrote: > > > > > > On 16/08/2023 19:07, Frank Li wrote: > > > > On Wed, Aug 16, 2023 at 06:47:17PM +0200, Daniel Lezcano wrote: > > > >> On 16/08/2023 18:28, Frank Li wrote: > > > >>> On Wed, Aug 16, 2023 at 10:44:32AM +0200, Daniel Lezcano wrote: > > > >>>> > > > >>>> Hi Frank, > > > >>>> > > > >>>> sorry for the delay > > > >>>> > > > >>>> On 14/07/2023 19:19, Frank Li wrote: > > > >>>>> On Thu, Jul 13, 2023 at 02:49:54PM +0200, Daniel Lezcano wrote: > > > >>>>>> On 12/07/2023 23:05, Frank Li wrote: > > > >>>>>>> Avoid endless print following message when SCFW turns off resource. > > > >>>>>>> [ 1818.342337] thermal thermal_zone0: failed to read out thermal zone (-1) > > > >>>>>>> > > > >>>>>>> Signed-off-by: Frank Li <Frank.Li@nxp.com> > > > >>>>>>> --- > > > >>>>>>> drivers/thermal/imx_sc_thermal.c | 4 +++- > > > >>>>>>> 1 file changed, 3 insertions(+), 1 deletion(-) > > > >>>>>>> > > > >>>>>>> diff --git a/drivers/thermal/imx_sc_thermal.c b/drivers/thermal/imx_sc_thermal.c > > > >>>>>>> index 8d6b4ef23746..0533d58f199f 100644 > > > >>>>>>> --- a/drivers/thermal/imx_sc_thermal.c > > > >>>>>>> +++ b/drivers/thermal/imx_sc_thermal.c > > > >>>>>>> @@ -58,7 +58,9 @@ static int imx_sc_thermal_get_temp(struct thermal_zone_device *tz, int *temp) > > > >>>>>>> hdr->size = 2; > > > >>>>>>> ret = imx_scu_call_rpc(thermal_ipc_handle, &msg, true); > > > >>>>>>> - if (ret) > > > >>>>>>> + if (ret == -EPERM) /* NO POWER */ > > > >>>>>>> + return -EAGAIN; > > > >>>>>> > > > >>>>>> Isn't there a chain call somewhere when the resource is turned off, so the > > > >>>>>> thermal zone can be disabled? > > > >>>>> > > > >>>>> A possible place in drivers/firmware/imx/scu-pd.c. but I am not sure how to > > > >>>>> get thermal devices. I just found a API thermal_zone_get_zone_by_name(). I > > > >>>>> am not sure if it is good to depend on "name", which add coupling between > > > >>>>> two drivers and if there are external thermal devices(such as) has the > > > >>>>> same name, it will wrong turn off. > > > >>>> > > > >>>> Correct > > > >>>> > > > >>>>> If add power domain notification in thermal driver, I am not how to get > > > >>>>> other devices's pd in thermal driver. > > > >>>>> > > > >>>>> Any example I can refer? > > > >>>>> > > > >>>>> Or this is simple enough solution. > > > >>>> > > > >>>> The solution works for removing the error message but it does not solve the > > > >>>> root cause of the issue. The thermal zone keeps monitoring while the sensor > > > >>>> is down. > > > >>>> > > > >>>> So the question is why the sensor is shut down if it is in use? > > > >>> > > > >>> Do you know if there are any code I reference? I supposed it is quite common. > > > >> > > > >> Sorry, I don't get your comment > > > >> > > > >> What I meant is why is the sensor turned off if it is in use ? > > > > > > > > One typical example is cpu hotplug. The sensor is located CPU power domain. > > > > If CPU hotplug off, CPU power domain will be turn off. > > > > > > > > It doesn't make sensor keep monitor such sensor when CPU already power off. > > > > It doesn't make sensor to keep CPU power on just because want to get sensor > > > > data. > > > > > > > > Anthor example is GPU, if there are GPU0 and GPU1. Most case just GPU0 > > > > work. GPU1 may turn off when less loading. > > > > > > > > Ideally, thermal can get notification from power domain driver. > > > > when such power domain turn off, disable thermal zone. > > > > > > > > So far, I have not idea how to do that. > > > > > > Ulf, > > > > > > do you have a guidance to link the thermal zone and the power domain in > > > order to get a poweron/off notification leading to enable/disable the > > > thermal zone ? > > > > I don't know the details here, so apologize for my ignorance to start > > with. What platform is this? > > i.MX8QM.
Thanks!
> > > > > A vague idea could be to hook up the thermal sensor to the > > corresponding CPU power domain. Assuming the CPU power domain is > > modelled as a genpd provider, then this allows the driver for the > > thermal sensor to register for power-on/off notifications of the genpd > > (see dev_pm_genpd_add_notifier()). > > > > Can this work? > > I don't think. dev_pm_genpd_ad_notifier() need a dev, which binded to pd.
Yes, correct.
> > tsens: thermal-sensor { > compatible = "fsl,imx-sc-thermal"; > tsens-num = <6>; > #thermal-sensor-cells = <1>; > };
Are you saying that the above doesn't have a corresponding struct device created for it? That sounds like a problem that can be fixed, right? Not sure if it makes sense though.
> > we have 6 thermal-sensor, which assocated with 6 pd, > IMX_SC_R_SYSTEM, IMX_SC_R_PMIC_0, > IMX_SC_R_AP_0, IMX_SC_R_AP_1, > IMX_SC_R_GPU_0_PID0, IMX_SC_R_GPU_1_PID0, > IMX_SC_R_DRC_0 > > We don't want to hold PD on just because want to get temperature. GPU pd > consume much power.
Of course, that would be a bad idea it seems like.
The corresponding struct device that's hooked up to a genpd, can remain runtime suspended as long as you think it makes sense. Thus it would not keep the PM domain powered on when it isn't needed.
> > I want to register one callback at thermal-sensor driver, when GPU pd on, > enable thermal-zone. when GPU pd off, disable thermal zone.
Right, that should work fine too, I think. It seems like this is just a matter of modelling this correctly in DT, I have no strong opinion in this regard.
> > we can do more common way. > > gpu-thermal1 { > polling-delay-passive = <250>; > polling-delay = <2000>; > >>> pd=<&GPU1_PD> > thermal-sensors = <&tsens IMX_SC_R_GPU_1_PID0>; > > }; > > if GPU1_PD on, then gpu-thermal1 enable, > if GPU1_PD off, then gpu-thermal1 disable. >
Sounds like it's worth a try! Please keep me posted.
Kind regards Uffe
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