[Intel-gfx] [PATCH 1/2] drm/i915/gt: Don't do display work on platforms without display

[Ashutosh Dixit]

Do display work only on platforms with display. This avoids holding the
runtime PM wakeref for an additional 100+ ms after GT has been parked.

Bug: https://gitlab.freedesktop.org/drm/intel/-/issues/7025
Signed-off-by: Ashutosh Dixit <ashutosh.dixit at intel.com>
---
 drivers/gpu/drm/i915/gt/intel_gt_pm.c | 36 +++++++++++++++------------
 1 file changed, 20 insertions(+), 16 deletions(-)

diff --git a/drivers/gpu/drm/i915/gt/intel_gt_pm.c b/drivers/gpu/drm/i915/gt/intel_gt_pm.c
index f553e2173bdad..26aa2e979a148 100644
--- a/drivers/gpu/drm/i915/gt/intel_gt_pm.c
+++ b/drivers/gpu/drm/i915/gt/intel_gt_pm.c
@@ -70,19 +70,21 @@ static int __gt_unpark(struct intel_wakeref *wf)
 
 	GT_TRACE(gt, "\n");
 
-	/*
-	 * It seems that the DMC likes to transition between the DC states a lot
-	 * when there are no connected displays (no active power domains) during
-	 * command submission.
-	 *
-	 * This activity has negative impact on the performance of the chip with
-	 * huge latencies observed in the interrupt handler and elsewhere.
-	 *
-	 * Work around it by grabbing a GT IRQ power domain whilst there is any
-	 * GT activity, preventing any DC state transitions.
-	 */
-	gt->awake = intel_display_power_get(i915, POWER_DOMAIN_GT_IRQ);
-	GEM_BUG_ON(!gt->awake);
+	if (HAS_DISPLAY(i915) && INTEL_DISPLAY_ENABLED(i915)) {
+		/*
+		 * It seems that the DMC likes to transition between the DC states a lot
+		 * when there are no connected displays (no active power domains) during
+		 * command submission.
+		 *
+		 * This activity has negative impact on the performance of the chip with
+		 * huge latencies observed in the interrupt handler and elsewhere.
+		 *
+		 * Work around it by grabbing a GT IRQ power domain whilst there is any
+		 * GT activity, preventing any DC state transitions.
+		 */
+		gt->awake = intel_display_power_get(i915, POWER_DOMAIN_GT_IRQ);
+		GEM_BUG_ON(!gt->awake);
+	}
 
 	intel_rc6_unpark(&gt->rc6);
 	intel_rps_unpark(&gt->rps);
@@ -115,9 +117,11 @@ static int __gt_park(struct intel_wakeref *wf)
 	/* Everything switched off, flush any residual interrupt just in case */
 	intel_synchronize_irq(i915);
 
-	/* Defer dropping the display power well for 100ms, it's slow! */
-	GEM_BUG_ON(!wakeref);
-	intel_display_power_put_async(i915, POWER_DOMAIN_GT_IRQ, wakeref);
+	if (HAS_DISPLAY(i915) && INTEL_DISPLAY_ENABLED(i915)) {
+		/* Defer dropping the display power well for 100ms, it's slow! */
+		GEM_BUG_ON(!wakeref);
+		intel_display_power_put_async(i915, POWER_DOMAIN_GT_IRQ, wakeref);
+	}
 
 	return 0;
 }
-- 
2.34.1