Commit 89839e69 authored by Abhinav Kumar's avatar Abhinav Kumar Committed by Dmitry Baryshkov
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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: default avatarAbhinav Kumar <quic_abhinavk@quicinc.com>
Signed-off-by: default avatarJessica Zhang <quic_jesszhan@quicinc.com>
Reviewed-by: default avatarDmitry Baryshkov <dmitry.baryshkov@linaro.org>
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: default avatarDmitry Baryshkov <dmitry.baryshkov@linaro.org>
parent 85bdbd83

drivers/gpu/drm/msm/msm_atomic.c

+2 −0
Original line number Diff line number Diff line
@@ -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:

drivers/gpu/drm/msm/msm_kms.c

+4 −1
Original line number Diff line number Diff line
@@ -168,7 +168,10 @@ static int msm_kms_fault_handler(void *arg, unsigned long iova, int flags, void 
{

	struct msm_kms *kms = arg;



	if (atomic_read(&kms->fault_snapshot_capture) == 0) {

		msm_disp_snapshot_state(kms->dev);

		atomic_inc(&kms->fault_snapshot_capture);

	}



	return -ENOSYS;

}

drivers/gpu/drm/msm/msm_kms.h

+3 −0
Original line number Diff line number Diff line
@@ -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;