From 89839e69f6154feecd79bd01171375225b0296e9 Mon Sep 17 00:00:00 2001 From: Abhinav Kumar Date: Wed, 19 Feb 2025 11:49:21 -0800 Subject: [PATCH] drm/msm/dpu: rate limit snapshot capture for mmu faults There is no recovery mechanism in place yet to recover from mmu faults for DPU. We can only prevent the faults by making sure there is no misconfiguration. Rate-limit the snapshot capture for mmu faults to once per msm_atomic_commit_tail() as that should be sufficient to capture the snapshot for debugging otherwise there will be a lot of DPU snapshots getting captured for the same fault which is redundant and also might affect capturing even one snapshot accurately. Signed-off-by: Abhinav Kumar Signed-off-by: Jessica Zhang Reviewed-by: Dmitry Baryshkov Patchwork: https://patchwork.freedesktop.org/patch/638362/ Link: https://lore.kernel.org/r/20250219-abhinavk-smmu-fault-handler-v3-5-aa3f0bf4434a@quicinc.com Signed-off-by: Dmitry Baryshkov --- drivers/gpu/drm/msm/msm_atomic.c | 2 ++ drivers/gpu/drm/msm/msm_kms.c | 5 ++++- drivers/gpu/drm/msm/msm_kms.h | 3 +++ 3 files changed, 9 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/msm/msm_atomic.c b/drivers/gpu/drm/msm/msm_atomic.c index a7a2384044ff..83c4e6aca209 100644 --- a/drivers/gpu/drm/msm/msm_atomic.c +++ b/drivers/gpu/drm/msm/msm_atomic.c @@ -221,6 +221,8 @@ void msm_atomic_commit_tail(struct drm_atomic_state *state) kms->funcs->wait_flush(kms, crtc_mask); trace_msm_atomic_wait_flush_finish(crtc_mask); + atomic_set(&kms->fault_snapshot_capture, 0); + /* * Now that there is no in-progress flush, prepare the * current update: diff --git a/drivers/gpu/drm/msm/msm_kms.c b/drivers/gpu/drm/msm/msm_kms.c index 35b835e0f23a..b877278888e6 100644 --- a/drivers/gpu/drm/msm/msm_kms.c +++ b/drivers/gpu/drm/msm/msm_kms.c @@ -168,7 +168,10 @@ static int msm_kms_fault_handler(void *arg, unsigned long iova, int flags, void { struct msm_kms *kms = arg; - msm_disp_snapshot_state(kms->dev); + if (atomic_read(&kms->fault_snapshot_capture) == 0) { + msm_disp_snapshot_state(kms->dev); + atomic_inc(&kms->fault_snapshot_capture); + } return -ENOSYS; } diff --git a/drivers/gpu/drm/msm/msm_kms.h b/drivers/gpu/drm/msm/msm_kms.h index e60162744c66..3e28c4e012d2 100644 --- a/drivers/gpu/drm/msm/msm_kms.h +++ b/drivers/gpu/drm/msm/msm_kms.h @@ -128,6 +128,9 @@ struct msm_kms { int irq; bool irq_requested; + /* rate limit the snapshot capture to once per attach */ + atomic_t fault_snapshot_capture; + /* mapper-id used to request GEM buffer mapped for scanout: */ struct msm_gem_address_space *aspace; -- 2.50.1