[Intel-gfx] [PATCH 01/11] drm/i915: Accurately track when we mark the hardware as idle/busy

[Chris Wilson]

On Fri, Feb 21, 2014 at 02:04:32PM -0300, Paulo Zanoni wrote:
> 2014-02-21 13:55 GMT-03:00 Chris Wilson <chris at chris-wilson.co.uk>:
> > On Fri, Feb 21, 2014 at 01:52:18PM -0300, Paulo Zanoni wrote:
> >> From: Chris Wilson <chris at chris-wilson.co.uk>
> >>
> >> We currently call intel_mark_idle() too often, as we do so as a
> >> side-effect of processing the request queue. However, we the calls to
> >> intel_mark_idle() are expected to be paired with a call to
> >> intel_mark_busy() (or else we try to idle the hardware by accessing
> >> registers that are already disabled). Make the idle/busy tracking
> >> explicit to prevent the multiple calls.
> >>
> >> v2: From Paulo
> >>   - Make it compile
> >>   - Drop the __i915_add_request chunk
> >>
> >> Reported-by: Paulo Zanoni <paulo.r.zanoni at intel.com>
> >> Tested-by: Paulo Zanoni <paulo.r.zanoni at intel.com>
> >> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> >> Cc: Paulo Zanoni <paulo.r.zanoni at intel.com>
> >> Signed-off-by: Paulo Zanoni <paulo.r.zanoni at intel.com>
> >> ---
> >>  drivers/gpu/drm/i915/i915_drv.h      | 8 ++++++++
> >>  drivers/gpu/drm/i915/intel_display.c | 9 +++++++++
> >>  2 files changed, 17 insertions(+)
> >>
> >>
> >> Chris did not reply to my review comments yet, so I just went and implemented
> >> them. We need at least an ACK form him here before merging.
> >
> > Didn't see them... Why have you altered the logic?
> 
> See the comment at the __i915_add_request chunk:
> 
> http://lists.freedesktop.org/archives/intel-gfx/2014-February/040334.html

Oh, I didn't look for comments inline.
> 
> Maybe I just broke your patch :)
> If my review doesn't make sense, we can stick to your version, it
> should do the job, and I can retest everything easily.

If there was a pending work item, the call to intel_mark_busy() would
return false. So we can revamp the logic around there a little bit. The
reason for the change should be self-evident - the previous code lost its
way in the transition to multiple rings arguing over a global property.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre