On Tue, Aug 4, 2020 at 4:32 AM Kalyan Thota <kalyan_t@xxxxxxxxxxxxxx> wrote:
>
> DPU resources reserved in the atomic_check path gets unwinded
> during modeset operation before commit happens in a non seamless
> transition.
>
> Update the reservations in the commit path to avoid resource
> failures. Secondly have dummy reservations in atomic_check path
> so that we can gracefully fail the composition if resources are
> not available.
>
> Signed-off-by: Kalyan Thota <kalyan_t@xxxxxxxxxxxxxx>
> ---
> drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c | 15 +++++++++++----
> 1 file changed, 11 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> index 63976dc..c6b8254 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> @@ -565,7 +565,7 @@ static int dpu_encoder_virt_atomic_check(
> const struct drm_display_mode *mode;
> struct drm_display_mode *adj_mode;
> struct msm_display_topology topology;
> - struct dpu_global_state *global_state;
> + struct dpu_global_state tmp_resv_state;
> int i = 0;
> int ret = 0;
>
> @@ -582,7 +582,7 @@ static int dpu_encoder_virt_atomic_check(
> dpu_kms = to_dpu_kms(priv->kms);
> mode = &crtc_state->mode;
> adj_mode = &crtc_state->adjusted_mode;
> - global_state = dpu_kms_get_existing_global_state(dpu_kms);
> + memset(&tmp_resv_state, 0, sizeof(tmp_resv_state));
I think what you want to do is dpu_kms_get_global_state().. that will
clone/duplicate the existing global state (or return the already
duplicated global state if it is called multiple times).
It is safe to modify this global state in the atomic_check() path.. in
fact that is the intention. For a TEST_ONLY atomic commit, or if any
of the atomic_check()'s fail, this new duplicated global state is
discarded. If all the checks succeed and the atomic update is
committed to hw, this new global state replaces the existing global
state.
BR,
-R
> trace_dpu_enc_atomic_check(DRMID(drm_enc));
>
> /*
> @@ -621,7 +621,7 @@ static int dpu_encoder_virt_atomic_check(
> * info may not be available to complete reservation.
> */
> if (drm_atomic_crtc_needs_modeset(crtc_state)) {
> - ret = dpu_rm_reserve(&dpu_kms->rm, global_state,
> + ret = dpu_rm_reserve(&dpu_kms->rm, &tmp_resv_state,
> drm_enc, crtc_state, topology);
> }
> }
> @@ -966,7 +966,7 @@ static void dpu_encoder_virt_mode_set(struct drm_encoder *drm_enc,
> struct dpu_hw_blk *hw_lm[MAX_CHANNELS_PER_ENC];
> struct dpu_hw_blk *hw_dspp[MAX_CHANNELS_PER_ENC] = { NULL };
> int num_lm, num_ctl, num_pp, num_dspp;
> - int i, j;
> + int i, j, rc;
>
> if (!drm_enc) {
> DPU_ERROR("invalid encoder\n");
> @@ -1006,6 +1006,13 @@ static void dpu_encoder_virt_mode_set(struct drm_encoder *drm_enc,
>
> topology = dpu_encoder_get_topology(dpu_enc, dpu_kms, adj_mode);
>
> + rc = dpu_rm_reserve(&dpu_kms->rm, global_state, drm_enc,
> + drm_crtc->state, topology);
> + if (rc) {
> + DPU_ERROR_ENC(dpu_enc, "Failed to reserve resources\n");
> + return;
> + }
> +
> /* Query resource that have been reserved in atomic check step. */
> num_pp = dpu_rm_get_assigned_resources(&dpu_kms->rm, global_state,
> drm_enc->base.id, DPU_HW_BLK_PINGPONG, hw_pp,
> --
> 1.9.1
>
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