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| author | Tvrtko Ursulin <tvrtko.ursulin@intel.com> | 2018-02-08 19:00:36 +0300 |
|---|---|---|
| committer | Tvrtko Ursulin <tvrtko.ursulin@intel.com> | 2018-02-13 19:30:17 +0300 |
| commit | 817cc07918232e0c3b4cf2926c1a08c8d08edc33 (patch) | |
| tree | 247017639415e52e571bf5e8511e038b7bd3de31 /drivers/gpu/drm/i915/i915_drv.h | |
| parent | 62b5ed1f35d7f6f140cc9de818991df4f11adc69 (diff) | |
| download | linux-817cc07918232e0c3b4cf2926c1a08c8d08edc33.tar.xz | |
drm/i915: Handle RC6 counter wrap
We can implement limited RC6 counter wrap-around protection under the
assumption that clients will be reading this value more frequently than
the wrap period on a given platform.
With the typical wrap-around period being ~90 minutes, even with the
exception of Baytrail which wraps every 13 seconds, this sounds like a
reasonable assumption.
Implementation works by storing a 64-bit software copy of a hardware RC6
counter, along with the previous HW counter snapshot. This enables it to
detect wrap is polled frequently enough and keep the software copy
monotonically incrementing.
v2:
* Missed GEN6_GT_GFX_RC6_LOCKED when considering slot sizing and
indexing.
* Fixed off-by-one in wrap-around handling. (Chris Wilson)
v3:
* Simplify index checking by using unsigned int. (Chris Wilson)
* Expand the comment to explain why indexing works.
v4:
* Use __int128 if supported.
v5:
* Use mul_u64_u32_div. (Chris Wilson)
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=94852
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk> # v3
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20180208160036.29919-1-tvrtko.ursulin@linux.intel.com
Acked-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Diffstat (limited to 'drivers/gpu/drm/i915/i915_drv.h')
| -rw-r--r-- | drivers/gpu/drm/i915/i915_drv.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h index 0bb8ad23efa7..ffbe397c2ade 100644 --- a/drivers/gpu/drm/i915/i915_drv.h +++ b/drivers/gpu/drm/i915/i915_drv.h @@ -947,6 +947,8 @@ struct intel_rps { struct intel_rc6 { bool enabled; + u64 prev_hw_residency[4]; + u64 cur_residency[4]; }; struct intel_llc_pstate { |