[Intel-gfx] [PATCH] drm/i915: add multi-threaded forcewake support

[Ben Widawsky]

On Fri, 18 Nov 2011 15:27:14 -0800
Keith Packard <keithp at keithp.com> wrote:

> On Fri, 18 Nov 2011 14:48:39 -0800, Jesse Barnes <jbarnes at virtuousgeek.org> wrote:
> 
> > So the ECOBUS reg *is* in the GT power well.  Which means in order to
> > read it we have to disable RC6 altogether, forcibly, using the 0xa090
> > reg, set up force wake, then re-enable RC6.
> 
> Not surprising the ECOBUS is in the well; we really only need to read it
> when rc6 is getting set up, so it'll be disabled at that point.
> 
> But, unless I'm confused, ECOBUS doesn't have any useful information in
> it anyways:
> 
> # intel_reg_read 0xa090
> 0xA090 : 0x0
> # intel_reg_read 0xa080
> 0xA080 : 0x0
> 

Are you using the forcewaked tool to read it?

bwidawsk at seagal ~/intel-gfx/drm-intel2 (forced-throttling|REBASE-i)$ sudo ../intel-gpu-tools/tools/intel_reg_read 0xa090
0xA090 : 0x88060000