[PATCH] amdgpu: Don't print L2 status if there's nothing to print

[Kent Russell]

If a 2nd fault comes in before the 1st is handled, the 1st fault will
clear out the FAULT STATUS registers before the 2nd fault is handled.
Thus we get a lot of zeroes. If status=0, just skip the L2 fault status
information, to avoid confusion of why some VM fault status prints in
dmesg are all zeroes.

Signed-off-by: Kent Russell <kent.russell at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/gmc_v10_0.c | 10 ++++++++++
 drivers/gpu/drm/amd/amdgpu/gmc_v11_0.c | 10 ++++++++++
 drivers/gpu/drm/amd/amdgpu/gmc_v12_0.c | 10 ++++++++++
 drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c  | 10 ++++++++++
 4 files changed, 40 insertions(+)

diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v10_0.c b/drivers/gpu/drm/amd/amdgpu/gmc_v10_0.c
index 5cf2002fcba8..14a52c33bffa 100644
--- a/drivers/gpu/drm/amd/amdgpu/gmc_v10_0.c
+++ b/drivers/gpu/drm/amd/amdgpu/gmc_v10_0.c
@@ -175,6 +175,16 @@ static int gmc_v10_0_process_interrupt(struct amdgpu_device *adev,
 			addr, entry->client_id,
 			soc15_ih_clientid_name[entry->client_id]);
 
+	/* If status=0, we don't have anything to process. Most often, this is
+	 * caused by a 2nd fault coming in before the 1st one is handled.
+	 * Once the 1st fault is handled, the fault registers are cleared, so
+	 * we have nothing to print for fault #2. In that case, don't try to
+	 * print the fault status information. The information above is
+	 * sufficient to note that another fault occurred.
+	 */
+	if (!status)
+		return 0;
+
 	if (!amdgpu_sriov_vf(adev))
 		hub->vmhub_funcs->print_l2_protection_fault_status(adev,
 								   status);
diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v11_0.c b/drivers/gpu/drm/amd/amdgpu/gmc_v11_0.c
index 4df4d73038f8..c5fe31070cf3 100644
--- a/drivers/gpu/drm/amd/amdgpu/gmc_v11_0.c
+++ b/drivers/gpu/drm/amd/amdgpu/gmc_v11_0.c
@@ -144,6 +144,16 @@ static int gmc_v11_0_process_interrupt(struct amdgpu_device *adev,
 		dev_err(adev->dev, "  in page starting at address 0x%016llx from client %d\n",
 				addr, entry->client_id);
 
+		/* If status=0, we don't have anything to process. Most often, this is
+		 * caused by a 2nd fault coming in before the 1st one is handled.
+		 * Once the 1st fault is handled, the fault registers are cleared, so
+		 * we have nothing to print for fault #2. In that case, don't try to
+		 * print the fault status information. The information above is
+		 * sufficient to note that another fault occurred.
+		 */
+		if (!status)
+			return 0;
+
 		if (!amdgpu_sriov_vf(adev))
 			hub->vmhub_funcs->print_l2_protection_fault_status(adev, status);
 	}
diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v12_0.c b/drivers/gpu/drm/amd/amdgpu/gmc_v12_0.c
index e33f9e9058cc..fcfe512f1271 100644
--- a/drivers/gpu/drm/amd/amdgpu/gmc_v12_0.c
+++ b/drivers/gpu/drm/amd/amdgpu/gmc_v12_0.c
@@ -137,6 +137,16 @@ static int gmc_v12_0_process_interrupt(struct amdgpu_device *adev,
 		dev_err(adev->dev, "  in page starting at address 0x%016llx from client %d\n",
 				addr, entry->client_id);
 
+		/* If status=0, we don't have anything to process. Most often, this is
+		 * caused by a 2nd fault coming in before the 1st one is handled.
+		 * Once the 1st fault is handled, the fault registers are cleared, so
+		 * we have nothing to print for fault #2. In that case, don't try to
+		 * print the fault status information. The information above is
+		 * sufficient to note that another fault occurred.
+		 */
+		if (!status)
+			return 0;
+
 		if (!amdgpu_sriov_vf(adev))
 			hub->vmhub_funcs->print_l2_protection_fault_status(adev, status);
 	}
diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c b/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
index 010db0e58650..6da2ca28375e 100644
--- a/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
+++ b/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
@@ -675,6 +675,16 @@ static int gmc_v9_0_process_interrupt(struct amdgpu_device *adev,
 	if (!amdgpu_sriov_vf(adev))
 		WREG32_P(hub->vm_l2_pro_fault_cntl, 1, ~1);
 
+	/* If status=0, we don't have anything to process. Most often, this is
+	 * caused by a 2nd fault coming in before the 1st one is handled.
+	 * Once the 1st fault is handled, the fault registers are cleared, so
+	 * we have nothing to print for fault #2. In that case, don't try to
+	 * print the fault status information. The information above is
+	 * sufficient to note that another fault occurred.
+	 */
+	if (!status)
+		return 0;
+
 	amdgpu_vm_update_fault_cache(adev, entry->pasid, addr, status, vmhub);
 
 	dev_err(adev->dev,
-- 
2.43.0