[PATCH v1] drm/i915/guc: Always disable interrupt ahead of synchronize_irq

[Zhanjun Dong]

The purpose of synchronize_irq is to wait for any pending IRQ handlers for the
interrupt to complete, if synchronize_irq called before interrupt disabled, an
tiny timing window created, where no more pending IRQ, but interrupt not
disabled yet. Meanwhile, if the interrupt event happened in this timing window,
an unexpected IRQ handling will be triggered.

Fixed by always disable interrupt ahead of synchronize_irq.

Closes: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/13454
Fixes: 26705e20752a ("drm/i915: Support for GuC interrupts")
Fixes: 54c52a841250 ("drm/i915/guc: Correctly handle GuC interrupts on Gen11")
Fixes: 2ae096872a2c ("drm/i915/pxp: Implement PXP irq handler")
Fixes: 3e7abf814193 ("drm/i915: Extract GT render power state management")

Signed-off-by: Zhanjun Dong <zhanjun.dong at intel.com>

---
Cc: Alan Previn <alan.previn.teres.alexis at intel.com>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
Cc: Michal Wajdeczko <michal.wajdeczko at intel.com>
Cc: Andi Shyti <andi.shyti at intel.com>
---
 drivers/gpu/drm/i915/gt/intel_rps.c      | 3 +--
 drivers/gpu/drm/i915/gt/uc/intel_guc.c   | 4 ++--
 drivers/gpu/drm/i915/pxp/intel_pxp_irq.c | 2 +-
 3 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/i915/gt/intel_rps.c b/drivers/gpu/drm/i915/gt/intel_rps.c
index fa304ea088e4..0fe7a8d7f460 100644
--- a/drivers/gpu/drm/i915/gt/intel_rps.c
+++ b/drivers/gpu/drm/i915/gt/intel_rps.c
@@ -244,8 +244,8 @@ static void rps_disable_interrupts(struct intel_rps *rps)
 	gen6_gt_pm_disable_irq(gt, GEN6_PM_RPS_EVENTS);
 	spin_unlock_irq(gt->irq_lock);
 
+	rps_reset_interrupts(rps);
 	intel_synchronize_irq(gt->i915);
-
 	/*
 	 * Now that we will not be generating any more work, flush any
 	 * outstanding tasks. As we are called on the RPS idle path,
@@ -254,7 +254,6 @@ static void rps_disable_interrupts(struct intel_rps *rps)
 	 */
 	cancel_work_sync(&rps->work);
 
-	rps_reset_interrupts(rps);
 	GT_TRACE(gt, "interrupts:off\n");
 }
 
diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc.c b/drivers/gpu/drm/i915/gt/uc/intel_guc.c
index 5949ff0b0161..3e7b2c6cdca4 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc.c
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc.c
@@ -116,9 +116,9 @@ static void gen9_disable_guc_interrupts(struct intel_guc *guc)
 	gen6_gt_pm_disable_irq(gt, gt->pm_guc_events);
 
 	spin_unlock_irq(gt->irq_lock);
-	intel_synchronize_irq(gt->i915);
 
 	gen9_reset_guc_interrupts(guc);
+	intel_synchronize_irq(gt->i915);
 }
 
 static bool __gen11_reset_guc_interrupts(struct intel_gt *gt)
@@ -154,9 +154,9 @@ static void gen11_disable_guc_interrupts(struct intel_guc *guc)
 	struct intel_gt *gt = guc_to_gt(guc);
 
 	guc->interrupts.enabled = false;
-	intel_synchronize_irq(gt->i915);
 
 	gen11_reset_guc_interrupts(guc);
+	intel_synchronize_irq(gt->i915);
 }
 
 static void guc_dead_worker_func(struct work_struct *w)
diff --git a/drivers/gpu/drm/i915/pxp/intel_pxp_irq.c b/drivers/gpu/drm/i915/pxp/intel_pxp_irq.c
index d81750b9bdda..b82a667e7ac0 100644
--- a/drivers/gpu/drm/i915/pxp/intel_pxp_irq.c
+++ b/drivers/gpu/drm/i915/pxp/intel_pxp_irq.c
@@ -101,9 +101,9 @@ void intel_pxp_irq_disable(struct intel_pxp *pxp)
 	__pxp_set_interrupts(gt, 0);
 
 	spin_unlock_irq(gt->irq_lock);
-	intel_synchronize_irq(gt->i915);
 
 	pxp_irq_reset(gt);
+	intel_synchronize_irq(gt->i915);
 
 	flush_work(&pxp->session_work);
 }
-- 
2.34.1