[Intel-gfx] [PATCH] drm/i915: add energy counter support for IVB

[Daniel Vetter]

On Wed, Jun 20, 2012 at 5:53 PM, Chris Wilson <chris at chris-wilson.co.uk> wrote:
> On Wed, 20 Jun 2012 08:32:59 -0700, Jesse Barnes <jbarnes at virtuousgeek.org> wrote:
>> On Wed, 20 Jun 2012 09:38:25 +0200
>> Daniel Vetter <daniel at ffwll.ch> wrote:
>> > And from the bikeshed departement: Can't we just print a running number? I
>> > know, substraction is bloody hard, but for anything else than total power
>> > consumption (e.g. graphing power over time) the running thing is imo
>> > simpler. We've had the same discussion for the rc6 sysfs residency timers
>> > and concluded (after Arjan yelled at us) that doing the substraction in
>> > userspace is better, least it allows multiple userspace tools to read
>> > this.
>> >
>>
>> Yeah that's a good point; this way happened to be simpler for what I
>> was doing, but just exposing the cooked register value (converted to
>> ujoules) is better.  Will fix.
>
> And to keep it easy to parse, just make it return -ENODEV on older
> platforms and a simple number for gen6+.

At that point you might also add the uJ suffix and move it to sysfs ;-)
-Daniel
-- 
Daniel Vetter
daniel.vetter at ffwll.ch - +41 (0) 79 364 57 48 - http://blog.ffwll.ch