[Intel-gfx] [PATCH] drm/i915/gt: Update PMINTRMSK holding fw

[Chris Wilson]

If we use a non-forcewaked write to PMINTRMSK, it does not take effect
until much later, if at all, causing a loss of RPS interrupts and no GPU
reclocking, leaving the GPU running at the wrong frequency for long
periods of time.

Reported-by: Francisco Jerez <currojerez at riseup.net>
Suggested-by: Francisco Jerez <currojerez at riseup.net>
Fixes: 35cc7f32c298 ("drm/i915/gt: Use non-forcewake writes for RPS")
Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Francisco Jerez <currojerez at riseup.net>
Cc: Mika Kuoppala <mika.kuoppala at linux.intel.com>
Cc: Andi Shyti <andi.shyti at intel.com>
Cc: <stable at vger.kernel.org> # v5.6+
---
 drivers/gpu/drm/i915/gt/intel_rps.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/gt/intel_rps.c b/drivers/gpu/drm/i915/gt/intel_rps.c
index 86110458e2a7..6a3505467406 100644
--- a/drivers/gpu/drm/i915/gt/intel_rps.c
+++ b/drivers/gpu/drm/i915/gt/intel_rps.c
@@ -81,13 +81,14 @@ static void rps_enable_interrupts(struct intel_rps *rps)
 		events = (GEN6_PM_RP_UP_THRESHOLD |
 			  GEN6_PM_RP_DOWN_THRESHOLD |
 			  GEN6_PM_RP_DOWN_TIMEOUT);
-
 	WRITE_ONCE(rps->pm_events, events);
+
 	spin_lock_irq(&gt->irq_lock);
 	gen6_gt_pm_enable_irq(gt, rps->pm_events);
 	spin_unlock_irq(&gt->irq_lock);
 
-	set(gt->uncore, GEN6_PMINTRMSK, rps_pm_mask(rps, rps->cur_freq));
+	intel_uncore_write(gt->uncore,
+                           GEN6_PMINTRMSK, rps_pm_mask(rps, rps->last_freq));
 }
 
 static void gen6_rps_reset_interrupts(struct intel_rps *rps)
@@ -120,7 +121,9 @@ static void rps_disable_interrupts(struct intel_rps *rps)
 	struct intel_gt *gt = rps_to_gt(rps);
 
 	WRITE_ONCE(rps->pm_events, 0);
-	set(gt->uncore, GEN6_PMINTRMSK, rps_pm_sanitize_mask(rps, ~0u));
+
+	intel_uncore_write(gt->uncore,
+                           GEN6_PMINTRMSK, rps_pm_sanitize_mask(rps, ~0u));
 
 	spin_lock_irq(&gt->irq_lock);
 	gen6_gt_pm_disable_irq(gt, GEN6_PM_RPS_EVENTS);
-- 
2.20.1