[PATCH 08/10] drm/amdgpu/gmc6: Delegate VM faults to soft IRQ handler ring

["Timur Kristóf" <timur.kristof@gmail.com>]

On old GPUs, it may be an issue that handling the interrupts from
VM faults is too slow and the interrupt handler (IH) ring may
overflow, which can cause an eventual hang.

Delegate the processing of all VM faults to the soft
IRQ handler ring.

As a result, we spend much less time in the IRQ handler that
interacts with the HW IH ring, which significantly reduces the
chance of hangs/reboots.

Signed-off-by: Timur Kristóf <timur.kristof@gmail.com>
---
 drivers/gpu/drm/amd/amdgpu/gmc_v6_0.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v6_0.c b/drivers/gpu/drm/amd/amdgpu/gmc_v6_0.c
index bc6a74903f4e..a8ec95f42926 100644
--- a/drivers/gpu/drm/amd/amdgpu/gmc_v6_0.c
+++ b/drivers/gpu/drm/amd/amdgpu/gmc_v6_0.c
@@ -1070,6 +1070,12 @@ static int gmc_v6_0_process_interrupt(struct amdgpu_device *adev,
 {
 	u32 addr, status;
 
+	/* Delegate to the soft IRQ handler ring */
+	if (adev->irq.ih_soft.enabled && entry->ih != &adev->irq.ih_soft) {
+		amdgpu_irq_delegate(adev, entry, 4);
+		return 1;
+	}
+
 	addr = RREG32(mmVM_CONTEXT1_PROTECTION_FAULT_ADDR);
 	status = RREG32(mmVM_CONTEXT1_PROTECTION_FAULT_STATUS);
 	WREG32_P(mmVM_CONTEXT1_CNTL2, 1, ~1);
-- 
2.51.1