From: Ionut Nechita <[email protected]>

After resume from hibernation, the amdgpu driver experiences TLB
flush failures with errors:

  amdgpu: TLB flush failed for PASID xxxxx
  amdgpu: failed to write reg 28b4 wait reg 28c6
  amdgpu: failed to write reg 1a6f4 wait reg 1a706

Root Cause:
-----------
The KIQ (Kernel Interface Queue) ring is marked as ready
(ring.sched.ready = true) during resume, but the hardware is not
fully functional yet. When TLB invalidation attempts to use KIQ
for register access, the commands fail because the GPU hasn't
completed initialization.

Solution:
---------
1. Add resume_gpu_stable flag (initially false on resume)
2. Force TLB invalidation to use direct MMIO path instead of KIQ
   when resume_gpu_stable is false
3. After ring tests pass in gfx_v9_0_cp_resume(), set
   resume_gpu_stable to true
4. From that point forward, use faster KIQ path for TLB invalidation

This ensures TLB flushes work correctly during early resume while
still benefiting from KIQ-based invalidation after the GPU is stable.

Changes:
--------
- amdgpu.h: Add resume_gpu_stable flag to amdgpu_device
- amdgpu_device.c: Initialize resume_gpu_stable to false on resume
- amdgpu_gmc.c: Check resume_gpu_stable in flush_gpu_tlb_pasid
- gfx_v9_0.c: Set resume_gpu_stable after ring tests pass
- gmc_v9_0.c: Check resume_gpu_stable before using KIQ path

Tested on AMD Cezanne (Renoir) with ROCm workloads after hibernation.
Result: Eliminates TLB flush failures on resume.

Signed-off-by: Ionut Nechita <[email protected]>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu.h        |  1 +
 drivers/gpu/drm/amd/amdgpu/amdgpu_device.c |  6 ++++++
 drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c    |  9 +++++++--
 drivers/gpu/drm/amd/amdgpu/gfx_v9_0.c      | 10 ++++++++++
 drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c      |  6 +++++-
 5 files changed, 29 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h 
b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
index 9f9774f58ce1c..6bf4f6c90164c 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
@@ -1225,6 +1225,7 @@ struct amdgpu_device {
        bool                            in_s4;
        bool                            in_s0ix;
        suspend_state_t                 last_suspend_state;
+       bool                            resume_gpu_stable;
 
        enum pp_mp1_state               mp1_state;
        struct amdgpu_doorbell_index doorbell_index;
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c 
b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index 12201b8e99b3f..440d86ed1e0d3 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -5457,6 +5457,12 @@ int amdgpu_device_resume(struct drm_device *dev, bool 
notify_clients)
                goto exit;
        }
 
+       /*
+        * Set resume_gpu_stable to false BEFORE KFD resume to ensure
+        * extended timeouts are used for TLB flushes during hibernation 
recovery
+        */
+       adev->resume_gpu_stable = false;
+
        r = amdgpu_amdkfd_resume(adev, !amdgpu_sriov_vf(adev) && 
!adev->in_runpm);
        if (r)
                goto exit;
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c 
b/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c
index 869bceb0fe2c6..83fe30f0ada75 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c
@@ -731,7 +731,12 @@ int amdgpu_gmc_flush_gpu_tlb_pasid(struct amdgpu_device 
*adev, uint16_t pasid,
        if (!down_read_trylock(&adev->reset_domain->sem))
                return 0;
 
-       if (!adev->gmc.flush_pasid_uses_kiq || !ring->sched.ready) {
+       /*
+        * After hibernation resume, KIQ may report as ready but not be fully
+        * functional. Use direct MMIO path until GPU is confirmed stable.
+        */
+       if (!adev->gmc.flush_pasid_uses_kiq || !ring->sched.ready ||
+           !adev->resume_gpu_stable) {
                if (adev->gmc.flush_tlb_needs_extra_type_2)
                        adev->gmc.gmc_funcs->flush_gpu_tlb_pasid(adev, pasid,
                                                                 2, all_hub,
@@ -835,9 +840,9 @@ void amdgpu_gmc_fw_reg_write_reg_wait(struct amdgpu_device 
*adev,
                goto failed_kiq;
 
        might_sleep();
+
        while (r < 1 && cnt++ < MAX_KIQ_REG_TRY &&
               !amdgpu_reset_pending(adev->reset_domain)) {
-
                msleep(MAX_KIQ_REG_BAILOUT_INTERVAL);
                r = amdgpu_fence_wait_polling(ring, seq, MAX_KIQ_REG_WAIT);
        }
diff --git a/drivers/gpu/drm/amd/amdgpu/gfx_v9_0.c 
b/drivers/gpu/drm/amd/amdgpu/gfx_v9_0.c
index 0148d7ff34d99..fbd07b455b915 100644
--- a/drivers/gpu/drm/amd/amdgpu/gfx_v9_0.c
+++ b/drivers/gpu/drm/amd/amdgpu/gfx_v9_0.c
@@ -3985,6 +3985,16 @@ static int gfx_v9_0_cp_resume(struct amdgpu_device *adev)
                amdgpu_ring_test_helper(ring);
        }
 
+       /*
+        * After successful ring tests, mark GPU as stable for resume.
+        * This allows KIQ-based TLB invalidation to be used instead of
+        * slower direct MMIO path.
+        */
+       if (!adev->resume_gpu_stable) {
+               adev->resume_gpu_stable = true;
+               dev_info(adev->dev, "GPU rings verified, enabling KIQ path\n");
+       }
+
        gfx_v9_0_enable_gui_idle_interrupt(adev, true);
 
        return 0;
diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c 
b/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
index 8ad7519f7b581..8a0202f6b3e3c 100644
--- a/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
+++ b/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
@@ -855,9 +855,13 @@ static void gmc_v9_0_flush_gpu_tlb(struct amdgpu_device 
*adev, uint32_t vmid,
 
        /* This is necessary for SRIOV as well as for GFXOFF to function
         * properly under bare metal
+        *
+        * After hibernation resume, KIQ may report as ready but not be fully
+        * functional. Use direct MMIO path until GPU is confirmed stable.
         */
        if (adev->gfx.kiq[inst].ring.sched.ready &&
-           (amdgpu_sriov_runtime(adev) || !amdgpu_sriov_vf(adev))) {
+           (amdgpu_sriov_runtime(adev) || !amdgpu_sriov_vf(adev)) &&
+           adev->resume_gpu_stable) {
                uint32_t req = hub->vm_inv_eng0_req + hub->eng_distance * eng;
                uint32_t ack = hub->vm_inv_eng0_ack + hub->eng_distance * eng;
 
-- 
2.52.0

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