Hi Eduardo,

On Wed, 2016-05-04 at 20:06 -0700, Eduardo Valentin wrote:

On Thu, May 05, 2016 at 12:00:57AM +0200, Rafael J. Wysocki wrote:

quoted

On Wednesday, May 04, 2016 02:54:32 PM Srinivas Pandruvada wrote:

quoted

On Wed, 2016-05-04 at 23:49 +0200, Rafael J. Wysocki wrote:

quoted

On Tue, May 3, 2016 at 7:04 AM, Eduardo Valentin <edubezval@gma
il.com

quoted

wrote:

Currently, in an ACPI based system, the processor driver
registers
one cooling device per processor. However, the cooling device
type
is the same for each processor. For example, on a system with
four
processors, the sysfs reading of each cooling device would
look
like:
ebv@besouro ~ $ cat /sys/class/thermal/cooling_device*/type
Processor
Processor
Processor
Processor

which turns out to fine. But, some parts of the thermal code
may
use
type to identify participating devices in a thermal zone.
Besides,
adding notifications to user space may cause the production
of
messages
that may confuse the listener.

For this reason, this patch adds the processor ID cooling
device
type.
After this change, the cooling device listing in the same
previous
example
would look like this:
ebv@besouro ~ $ cat /sys/class/thermal/cooling_device*/type
Processor.0
Processor.1
Processor.2
Processor.3

allowing an easier identification of cooling device target.

Is it not going to confuse any user space scripts or similar?

Yes, it will.

In that case the patch cannot be applied.

In fact, we shall never brake userspace. 

Srinivas, could you please elaborate a bit more on how this would
break
userspace? How different would it be having an extra id? Are you
expecting "Processor" string in daemon?

Yes.
Also Processor is a special type of cdev on client systems. So you set
a state in one Processor all Processors cooling device gets changed as
they share voltage and frequency. So they all are same. So if some user
space tries to reduce the cur_state by 1 for all the processor cooling
devices they will effectively reduce cur_state to much lower value.

So instead of this, we should have only one processor cooling device
per CPU package, so on most of the client systems, we will see only one
processor cooling device.

Thanks,
Srinivas

BR,

quoted

Thanks,
Rafael