Messages in this thread | | | From | Wei Wang <> | Date | Wed, 11 Dec 2019 14:19:03 -0800 | Subject | Re: [PATCH v3 0/3] thermal: introduce by-name softlink |
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On Wed, Dec 11, 2019 at 1:11 PM Daniel Lezcano <daniel.lezcano@linaro.org> wrote: > > On 11/12/2019 21:11, Wei Wang wrote: > > On Wed, Dec 11, 2019 at 12:54 AM Greg Kroah-Hartman > > <gregkh@linuxfoundation.org> wrote: > >> > >> On Tue, Dec 10, 2019 at 09:54:11PM +0100, Daniel Lezcano wrote: > >>> On 10/12/2019 21:01, Wei Wang wrote: > >>>> On Tue, Dec 10, 2019 at 6:36 AM Daniel Lezcano > >>>> <daniel.lezcano@linaro.org> wrote: > >>>>> > >>>>> On 05/12/2019 08:19, Wei Wang wrote: > >>>>>> The paths thermal_zone%d and cooling_device%d are not intuitive and the > >>>>>> numbers are subject to change due to device tree change. This usually > >>>>>> leads to tree traversal in userspace code. > >> > >> tree traversal is supposed to be done in userspace code :) > >> > > Yes, that can be done in userspace, but given the amount of thermal > > zones we have in some mobile devices, this will bring a lot of > > convenience. > > But usually all these thermal zones are fixed and building the name<->tz > association is just a question of a few lines of code from userspace, > no? What would be the benefit of adding more ABI?
code reuse as tz mapping is per device tree setup and we try to use the same _type_ in thermal zone in shared client code for Android thermal API.
> > If there is a thermal zone change, then a notification can be used, so > the userspace code rebuild the name<->tz, no?
Assuming you meant for type<->tz, this mapping won't change in runtime in our case (not unloading things), but it could be changed due to device tree change, e.g. adding/removing thermal zones.
> > > e.g. this is on Pixel 4 XL: > > coral:/ # ls /sys/devices/virtual/thermal/ > > cdev-by-name cooling_device15 cooling_device22 cooling_device3 > > cooling_device9 thermal_zone15 thermal_zone22 thermal_zone3 > > thermal_zone37 thermal_zone44 thermal_zone51 thermal_zone59 > > thermal_zone66 thermal_zone73 thermal_zone80 thermal_zone88 > > cooling_device0 cooling_device16 cooling_device23 cooling_device30 > > thermal_zone0 thermal_zone16 thermal_zone23 thermal_zone30 > > thermal_zone38 thermal_zone45 thermal_zone52 thermal_zone6 > > thermal_zone67 thermal_zone74 thermal_zone81 thermal_zone9 > > cooling_device1 cooling_device17 cooling_device24 cooling_device31 > > thermal_zone1 thermal_zone17 thermal_zone24 thermal_zone31 > > thermal_zone39 thermal_zone46 thermal_zone53 thermal_zone60 > > thermal_zone68 thermal_zone75 thermal_zone82 tz-by-name > > cooling_device10 cooling_device18 cooling_device25 cooling_device4 > > thermal_zone10 thermal_zone18 thermal_zone25 thermal_zone32 > > thermal_zone4 thermal_zone47 thermal_zone54 thermal_zone61 > > thermal_zone69 thermal_zone76 thermal_zone83 > > cooling_device11 cooling_device19 cooling_device26 cooling_device5 > > thermal_zone11 thermal_zone19 thermal_zone26 thermal_zone33 > > thermal_zone40 thermal_zone48 thermal_zone55 thermal_zone62 > > thermal_zone7 thermal_zone77 thermal_zone84 > > cooling_device12 cooling_device2 cooling_device27 cooling_device6 > > thermal_zone12 thermal_zone2 thermal_zone27 thermal_zone34 > > thermal_zone41 thermal_zone49 thermal_zone56 thermal_zone63 > > thermal_zone70 thermal_zone78 thermal_zone85 > > cooling_device13 cooling_device20 cooling_device28 cooling_device7 > > thermal_zone13 thermal_zone20 thermal_zone28 thermal_zone35 > > thermal_zone42 thermal_zone5 thermal_zone57 thermal_zone64 > > thermal_zone71 thermal_zone79 thermal_zone86 > > cooling_device14 cooling_device21 cooling_device29 cooling_device8 > > thermal_zone14 thermal_zone21 thermal_zone29 thermal_zone36 > > thermal_zone43 thermal_zone50 thermal_zone58 thermal_zone65 > > thermal_zone72 thermal_zone8 thermal_zone87 > > > > > >> But what userspace code needs to do this, and for what? > > In Android, thermal daemon and thermal HAL as well as some init.rc > > script would use those thermal paths for managing and monitoring > > thermal. The daemon/HAL could have logic pipled in, however Android's > > init.rc script would be really tricky. > > On a related note, we also create /dev/block/by-name links from userspace. > > > > Thanks! > > -Wei > >> > >> thanks, > >> > >> greg k-h > > > -- > <http://www.linaro.org/> Linaro.org │ Open source software for ARM SoCs > > Follow Linaro: <http://www.facebook.com/pages/Linaro> Facebook | > <http://twitter.com/#!/linaroorg> Twitter | > <http://www.linaro.org/linaro-blog/> Blog >
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