On Tue, Jan 07, 2014 at 02:44:10AM +0000, Wei Ni wrote: > On 01/06/2014 10:54 PM, Eduardo Valentin wrote: > > * PGP Signed by an unknown key > > > > On 06-01-2014 09:51, Mark Rutland wrote: > >> On Thu, Jan 02, 2014 at 05:50:06PM +0000, Matthew Longnecker wrote: > >>> > >>>> I think the platform driver may set governor for the thermal zone, > >>>> so how about to add a property named as "governor", > >>>> and parse it to tzp->governor_name, > >>>> something like: > >>>> ret = of_property_read_string(child, "governor", &str); > >>>> if (ret == 0) > >>>> if (strlen(str) < THERMAL_NAME_LENGTH) > >>>> strcpy(tzp->governor_name, str); > >>>> > >>>> Thanks. > >>>> Wei. > >>> > >>> DT is supposed to describe the hardware, right? The governor isn't > >>> hardware -- it's a software control policy. On the other hand, that > >>> control policy must be tuned according to the behaviors of the platform > >>> hardware otherwise the system will be unstable. > >>> > >>> Is it appropriate to be naming the governor in DT? If so, is it equally > >>> appropriate to describe any governor-specific parameters in DT (even > >>> though they are pure software constructs)? > >> > >> The dt should be relatively static -- if the hardware doesn't change the > >> dt shouldn't have to. > >> > >> The governers are not static. We can introduce new ones and throw away > >> old ones at any time. Tuning parameters can also change at any time. > >> > >> I'd prefer to not have governer details described in the dt, and the > >> choice of governer and configuration of its tuning parameters should be > >> made at runtime somehow. > > > > Agreed. > > Yes, I think so, but the of-thermal driver handle the > thermal_zone_device_register, and pass the "tzp" without governor_name, > so the created thermal_zone's governor will be NULL, then it can't run > into the governor->throttle() if needed. And currently there have no > interface to support updating governor and configuration at runtime. > I think it's better to initialize the governor_name when register the > thermal zone device in the of-thermal driver. Initialising it in the driver doesn't mean it has to come from the device tree. That's still a run-time decision, even though it's made immediately after parsing the DT. Thanks, Mark. -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
