[Intel-gfx] [PATCH] drm/i915: Idleness detection for DRRS

[Chris Wilson]

On Thu, Aug 07, 2014 at 07:15:15PM +0530, Vandana Kannan wrote:
> Adding support to detect display idleness by tracking page flip from
> user space. Switch to low refresh rate is triggered after 2 seconds of
> idleness. The delay is configurable. If there is a page flip or call to
> update the plane, then high refresh rate is applied.
> The feature is not used in dual-display mode.
> 
> v2: Chris Wilson's review comments incorporated.
> Modify idleness detection implementation to make it similar to the
> implementation of intel_update_fbc/intel_disable_fbc
> 
> v3: Internal review comments incorporated
> Add NULL pointer check in intel_disable_drrs.
> Add drrs calls in i9xx_crtc_enable/disable and valleyview_crtc_enable.
> 
> v4: Jani's review comments incorporated.
> Change in sequence in intel_update_drrs. Comment modified to remove details
> of update param. Modified DRRS idleness interval to a module parameter.
> 
> v5: Chris's review comments incorporated.
> Initialize connector in idleness detection init. Modifications made to
> use only intel_connector in i915_drrs and derive intel_dp when required.
> Added a function drrs_fini to cleanup DRRS work.
> 
> v6: Internal review comments. Removed check for primary enabled, which is
> a redundant check, in the case of clone mode. Added a flag to track
> dual-display configuration. Remove print statement for "cancel DRR work"
> and print "DRRS not supported" only once.
> 
> v7: As per internal review comments, removing calls to update/disable drrs
> from sprite update path. For sprite, all drrs related updates would be
> taken care of with calls to crtc page flip itself. This will have to be
> revisited later if flip infrastructure changes for sprite.
> 
> v8: Incorporated Jani's review comments. Added space after the periods in the
> module param description. Changes around drrs-fini to remove seamless DRRS
> check.
> 
> v9: Added checks for PSR before updating DRRS. Added check for module
> param drrs_interval before updating DRRS (this is required if the interval
> is modified by the user during system use). DRRS disabled by default. Changes
> based on Jani's review comments
> 
> v10: Disable/enable DRRS when PSR is enable/disabled.
> 
> v11: Moved DRRS not supported log to patch2.
> 
> Patch rebased.
> 
> Signed-off-by: Vandana Kannan <vandana.kannan at intel.com>
> Signed-off-by: Pradeep Bhat <pradeep.bhat at intel.com>
> Reviewed-by: Jani Nikula <jani.nikula at intel.com>
> Cc: Daniel Vetter <daniel at ffwll.ch>

Woohoo, we still want to introduce yet another idleness detector and
ignore the complexity of front buffer rendering.
-Chrsi

-- 
Chris Wilson, Intel Open Source Technology Centre