| Message ID | 20250219-abhinavk-smmu-fault-handler-v3-5-aa3f0bf4434a@quicinc.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
| Series | drm/msm: add a display mmu fault handler | expand |
On Wed, Feb 19, 2025 at 11:49:21AM -0800, Jessica Zhang wrote: > From: Abhinav Kumar <quic_abhinavk@quicinc.com> > > 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 <quic_abhinavk@quicinc.com> > Signed-off-by: Jessica Zhang <quic_jesszhan@quicinc.com> > --- > Changes in v3: > - Clear fault_snapshot_capture before calling prepare_commit() (Dmitry) > - Make fault_snapshot_capture an atomic variable (Dmitry, Abhinav) > --- > 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(-) > Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
diff --git a/drivers/gpu/drm/msm/msm_atomic.c b/drivers/gpu/drm/msm/msm_atomic.c index 9c45d641b521..44b402e70925 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 1d3dae3d4c93..171462a8e08c 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;