diff --git a/drivers/gpu/drm/amd/amdgpu/vega10_ih.c b/drivers/gpu/drm/amd/amdgpu/vega10_ih.c
index 88626d83e07beb..ca8efa5c6978d5 100644
--- a/drivers/gpu/drm/amd/amdgpu/vega10_ih.c
+++ b/drivers/gpu/drm/amd/amdgpu/vega10_ih.c
@@ -220,10 +220,8 @@ static int vega10_ih_enable_ring(struct amdgpu_device *adev,
 	tmp = vega10_ih_rb_cntl(ih, tmp);
 	if (ih == &adev->irq.ih)
 		tmp = REG_SET_FIELD(tmp, IH_RB_CNTL, RPTR_REARM, !!adev->irq.msi_enabled);
-	if (ih == &adev->irq.ih1) {
-		tmp = REG_SET_FIELD(tmp, IH_RB_CNTL, WPTR_OVERFLOW_ENABLE, 0);
+	if (ih == &adev->irq.ih1)
 		tmp = REG_SET_FIELD(tmp, IH_RB_CNTL, RB_FULL_DRAIN_ENABLE, 1);
-	}
 	if (amdgpu_sriov_vf(adev)) {
 		if (psp_reg_program(&adev->psp, ih_regs->psp_reg_id, tmp)) {
 			dev_err(adev->dev, "PSP program IH_RB_CNTL failed!\n");
@@ -265,7 +263,6 @@ static int vega10_ih_irq_init(struct amdgpu_device *adev)
 	u32 ih_chicken;
 	int ret;
 	int i;
-	u32 tmp;
 
 	/* disable irqs */
 	ret = vega10_ih_toggle_interrupts(adev, false);
@@ -291,15 +288,6 @@ static int vega10_ih_irq_init(struct amdgpu_device *adev)
 		}
 	}
 
-	tmp = RREG32_SOC15(OSSSYS, 0, mmIH_STORM_CLIENT_LIST_CNTL);
-	tmp = REG_SET_FIELD(tmp, IH_STORM_CLIENT_LIST_CNTL,
-			    CLIENT18_IS_STORM_CLIENT, 1);
-	WREG32_SOC15(OSSSYS, 0, mmIH_STORM_CLIENT_LIST_CNTL, tmp);
-
-	tmp = RREG32_SOC15(OSSSYS, 0, mmIH_INT_FLOOD_CNTL);
-	tmp = REG_SET_FIELD(tmp, IH_INT_FLOOD_CNTL, FLOOD_CNTL_ENABLE, 1);
-	WREG32_SOC15(OSSSYS, 0, mmIH_INT_FLOOD_CNTL, tmp);
-
 	pci_set_master(adev->pdev);
 
 	/* enable interrupts */
@@ -345,11 +333,17 @@ static u32 vega10_ih_get_wptr(struct amdgpu_device *adev,
 	u32 wptr, tmp;
 	struct amdgpu_ih_regs *ih_regs;
 
-	wptr = le32_to_cpu(*ih->wptr_cpu);
-	ih_regs = &ih->ih_regs;
+	if (ih == &adev->irq.ih) {
+		/* Only ring0 supports writeback. On other rings fall back
+		 * to register-based code with overflow checking below.
+		 */
+		wptr = le32_to_cpu(*ih->wptr_cpu);
 
-	if (!REG_GET_FIELD(wptr, IH_RB_WPTR, RB_OVERFLOW))
-		goto out;
+		if (!REG_GET_FIELD(wptr, IH_RB_WPTR, RB_OVERFLOW))
+			goto out;
+	}
+
+	ih_regs = &ih->ih_regs;
 
 	/* Double check that the overflow wasn't already cleared. */
 	wptr = RREG32_NO_KIQ(ih_regs->ih_rb_wptr);
@@ -440,15 +434,11 @@ static int vega10_ih_self_irq(struct amdgpu_device *adev,
 			      struct amdgpu_irq_src *source,
 			      struct amdgpu_iv_entry *entry)
 {
-	uint32_t wptr = cpu_to_le32(entry->src_data[0]);
-
 	switch (entry->ring_id) {
 	case 1:
-		*adev->irq.ih1.wptr_cpu = wptr;
 		schedule_work(&adev->irq.ih1_work);
 		break;
 	case 2:
-		*adev->irq.ih2.wptr_cpu = wptr;
 		schedule_work(&adev->irq.ih2_work);
 		break;
 	default: break;
diff --git a/drivers/gpu/drm/amd/amdgpu/vega20_ih.c b/drivers/gpu/drm/amd/amdgpu/vega20_ih.c
index 0049f048a30513..101416c646c748 100644
--- a/drivers/gpu/drm/amd/amdgpu/vega20_ih.c
+++ b/drivers/gpu/drm/amd/amdgpu/vega20_ih.c
@@ -223,10 +223,8 @@ static int vega20_ih_enable_ring(struct amdgpu_device *adev,
 	tmp = vega20_ih_rb_cntl(ih, tmp);
 	if (ih == &adev->irq.ih)
 		tmp = REG_SET_FIELD(tmp, IH_RB_CNTL, RPTR_REARM, !!adev->irq.msi_enabled);
-	if (ih == &adev->irq.ih1) {
-		tmp = REG_SET_FIELD(tmp, IH_RB_CNTL, WPTR_OVERFLOW_ENABLE, 0);
+	if (ih == &adev->irq.ih1)
 		tmp = REG_SET_FIELD(tmp, IH_RB_CNTL, RB_FULL_DRAIN_ENABLE, 1);
-	}
 	if (amdgpu_sriov_vf(adev)) {
 		if (psp_reg_program(&adev->psp, ih_regs->psp_reg_id, tmp)) {
 			dev_err(adev->dev, "PSP program IH_RB_CNTL failed!\n");
@@ -300,7 +298,6 @@ static int vega20_ih_irq_init(struct amdgpu_device *adev)
 	u32 ih_chicken;
 	int ret;
 	int i;
-	u32 tmp;
 
 	/* disable irqs */
 	ret = vega20_ih_toggle_interrupts(adev, false);
@@ -341,15 +338,6 @@ static int vega20_ih_irq_init(struct amdgpu_device *adev)
 		}
 	}
 
-	tmp = RREG32_SOC15(OSSSYS, 0, mmIH_STORM_CLIENT_LIST_CNTL);
-	tmp = REG_SET_FIELD(tmp, IH_STORM_CLIENT_LIST_CNTL,
-			    CLIENT18_IS_STORM_CLIENT, 1);
-	WREG32_SOC15(OSSSYS, 0, mmIH_STORM_CLIENT_LIST_CNTL, tmp);
-
-	tmp = RREG32_SOC15(OSSSYS, 0, mmIH_INT_FLOOD_CNTL);
-	tmp = REG_SET_FIELD(tmp, IH_INT_FLOOD_CNTL, FLOOD_CNTL_ENABLE, 1);
-	WREG32_SOC15(OSSSYS, 0, mmIH_INT_FLOOD_CNTL, tmp);
-
 	pci_set_master(adev->pdev);
 
 	/* enable interrupts */
@@ -395,11 +383,17 @@ static u32 vega20_ih_get_wptr(struct amdgpu_device *adev,
 	u32 wptr, tmp;
 	struct amdgpu_ih_regs *ih_regs;
 
-	wptr = le32_to_cpu(*ih->wptr_cpu);
-	ih_regs = &ih->ih_regs;
+	if (ih == &adev->irq.ih) {
+		/* Only ring0 supports writeback. On other rings fall back
+		 * to register-based code with overflow checking below.
+		 */
+		wptr = le32_to_cpu(*ih->wptr_cpu);
 
-	if (!REG_GET_FIELD(wptr, IH_RB_WPTR, RB_OVERFLOW))
-		goto out;
+		if (!REG_GET_FIELD(wptr, IH_RB_WPTR, RB_OVERFLOW))
+			goto out;
+	}
+
+	ih_regs = &ih->ih_regs;
 
 	/* Double check that the overflow wasn't already cleared. */
 	wptr = RREG32_NO_KIQ(ih_regs->ih_rb_wptr);
@@ -491,15 +485,11 @@ static int vega20_ih_self_irq(struct amdgpu_device *adev,
 			      struct amdgpu_irq_src *source,
 			      struct amdgpu_iv_entry *entry)
 {
-	uint32_t wptr = cpu_to_le32(entry->src_data[0]);
-
 	switch (entry->ring_id) {
 	case 1:
-		*adev->irq.ih1.wptr_cpu = wptr;
 		schedule_work(&adev->irq.ih1_work);
 		break;
 	case 2:
-		*adev->irq.ih2.wptr_cpu = wptr;
 		schedule_work(&adev->irq.ih2_work);
 		break;
 	default: break;