If we park/unpark faster than we can respond to RPS events, we never will process a downclock event after expiring a waitboost, and thus we will forever restart the GPU at max clocks even if the workload switches and doesn't justify full power. Closes: https://gitlab.freedesktop.org/drm/intel/issues/1500 Fixes: 3e7abf814193 ("drm/i915: Extract GT render power state management") Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> Cc: Andi Shyti <andi.shyti@xxxxxxxxx> Cc: Lyude Paul <lyude@xxxxxxxxxx> Reviewed-by: Andi Shyti <andi.shyti@xxxxxxxxx> Link: https://patchwork.freedesktop.org/patch/msgid/20200322163225.28791-1-chris@xxxxxxxxxxxxxxxxxx Cc: <stable@xxxxxxxxxxxxxxx> # v5.5+ (cherry picked from commit 21abf0bf168dffff1192e0f072af1dc74ae1ff0e) --- drivers/gpu/drm/i915/gt/intel_rps.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/drivers/gpu/drm/i915/gt/intel_rps.c b/drivers/gpu/drm/i915/gt/intel_rps.c index 3a3f49a71974..8accea06185b 100644 --- a/drivers/gpu/drm/i915/gt/intel_rps.c +++ b/drivers/gpu/drm/i915/gt/intel_rps.c @@ -765,6 +765,19 @@ void intel_rps_park(struct intel_rps *rps) intel_uncore_forcewake_get(rps_to_uncore(rps), FORCEWAKE_MEDIA); rps_set(rps, rps->idle_freq, false); intel_uncore_forcewake_put(rps_to_uncore(rps), FORCEWAKE_MEDIA); + + /* + * Since we will try and restart from the previously requested + * frequency on unparking, treat this idle point as a downclock + * interrupt and reduce the frequency for resume. If we park/unpark + * more frequently than the rps worker can run, we will not respond + * to any EI and never see a change in frequency. + * + * (Note we accommodate Cherryview's limitation of only using an + * even bin by applying it to all.) + */ + rps->cur_freq = + max_t(int, round_down(rps->cur_freq - 1, 2), rps->min_freq); } void intel_rps_boost(struct i915_request *rq) --------------------------------------------------------------------- Intel Corporation (UK) Limited Registered No. 1134945 (England) Registered Office: Pipers Way, Swindon SN3 1RJ VAT No: 860 2173 47 This e-mail and any attachments may contain confidential material for the sole use of the intended recipient(s). Any review or distribution by others is strictly prohibited. If you are not the intended recipient, please contact the sender and delete all copies.
