RE: [PATCH 4/8] Thermal: Add Thermal_trip sysfs node

[R, Durgadoss]

> -----Original Message-----
> From: Greg KH [mailto:gregkh@xxxxxxxxxxxxxxxxxxx]
> Sent: Thursday, December 20, 2012 9:42 PM
> To: R, Durgadoss
> Cc: Zhang, Rui; linux-pm@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> hongbo.zhang@xxxxxxxxxx; wni@xxxxxxxxxx
> Subject: Re: [PATCH 4/8] Thermal: Add Thermal_trip sysfs node
> 
> On Thu, Dec 20, 2012 at 07:52:03AM +0000, R, Durgadoss wrote:
> > > On Tue, Dec 18, 2012 at 02:59:33PM +0530, Durgadoss R wrote:
> > > > This patch adds a thermal_trip directory under
> > > > /sys/class/thermal/zoneX. This directory contains
> > > > the trip point values for sensors bound to this
> > > > zone.
> > >
> > > Eeek, you just broke userspace tools that now can no longer see these
> > > entries :(
> > >
> > > Why do you need to create a subdirectory?  As you found out, doing so
> > > isn't the easiest, right?  That is on purpose.
> >
> > Yes, I observed the complexity.
> >
> > >
> > > I really wouldn't recommend doing this at all, please stick within the
> > > 'struct device' framework here, don't create new kobjects and hang sysfs
> > > files off of them.
> >
> > But, we cannot put all _trip directly under ZoneX directory.
> 
> Why not?  What is preventing this?
> 
> > We can remove the thermal_trip directory, and put sensorY_trip under
> > /sys/class/thermal/zoneX/.  But this sensorY_trip needs to be a
> > directory which has four sysfs nodes named, active, passive, crit,
> > hot.
> >
> > Rui, What do you think about this ?
> >
> > The only other way I see, is directly put
> sensorY_trip_[active/passive/hot/crit]
> > which will create way too many nodes, under /sys/class/thermal/zoneX/.
> 
> What is "too many"?  20000?  50000?  How many are we talking about here?

Not in 1000's though..

> What is the limiting factor that is preventing this from all going into
> one directory?

We support a MAX of 12 sensors per zone today, which will lead to
12 * 4, 48 nodes under this directory named
sensorY_trip_[active/passive/hot/crit], besides the other nodes.

Thanks,
Durga
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