On Wed, Jan 21, 2026 at 04:01:51PM +0800, Jun Nie wrote:
> Currently, plane splitting and SSPP allocation occur during the plane
> check phase. Defer these operations until dpu_assign_plane_resources()
> is called from the CRTC side to ensure the topology information from
> the CRTC check is available.

Why is it important? What is broken otherwise?

> 
> Signed-off-by: Jun Nie <[email protected]>
> ---
>  drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c  |   3 +-
>  drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c | 112 
> +++++++++++++++++++-----------
>  2 files changed, 71 insertions(+), 44 deletions(-)
> 
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c 
> b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
> index 2d06c950e8143..debdbbe6160dd 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
> @@ -1484,8 +1484,7 @@ static int dpu_crtc_atomic_check(struct drm_crtc *crtc,
>                       return rc;
>       }
>  
> -     if (dpu_use_virtual_planes &&
> -         (crtc_state->planes_changed || crtc_state->zpos_changed)) {
> +     if (crtc_state->planes_changed || crtc_state->zpos_changed) {
>               rc = dpu_crtc_reassign_planes(crtc, crtc_state);
>               if (rc < 0)
>                       return rc;
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c 
> b/drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c
> index 66f240ce29d07..3c629f4df461d 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c
> @@ -1119,49 +1119,25 @@ static int dpu_plane_atomic_check(struct drm_plane 
> *plane,
>       struct drm_plane_state *new_plane_state = 
> drm_atomic_get_new_plane_state(state,
>                                                                               
>  plane);
>       int ret = 0;
> -     struct dpu_plane *pdpu = to_dpu_plane(plane);
> -     struct dpu_plane_state *pstate = to_dpu_plane_state(new_plane_state);
> -     struct dpu_kms *dpu_kms = _dpu_plane_get_kms(plane);
> -     struct dpu_sw_pipe *pipe = &pstate->pipe[0];
> -     struct dpu_sw_pipe *r_pipe = &pstate->pipe[1];
> -     struct dpu_sw_pipe_cfg *pipe_cfg = &pstate->pipe_cfg[0];
> -     struct dpu_sw_pipe_cfg *r_pipe_cfg = &pstate->pipe_cfg[1];
> -     const struct drm_crtc_state *crtc_state = NULL;
> -     uint32_t max_linewidth = dpu_kms->catalog->caps->max_linewidth;
> +     struct drm_crtc_state *crtc_state = NULL;
>  
>       if (new_plane_state->crtc)
>               crtc_state = drm_atomic_get_new_crtc_state(state,
>                                                          
> new_plane_state->crtc);
>  
> -     pipe->sspp = dpu_rm_get_sspp(&dpu_kms->rm, pdpu->pipe);
> -
> -     if (!pipe->sspp)
> -             return -EINVAL;
> -
>       ret = dpu_plane_atomic_check_nosspp(plane, new_plane_state, crtc_state);
>       if (ret)
>               return ret;
>  
> -     ret = dpu_plane_split(plane, new_plane_state, crtc_state);
> -     if (ret)
> -             return ret;
> -
>       if (!new_plane_state->visible)
>               return 0;
>  
> -     if (!dpu_plane_try_multirect_parallel(pipe, pipe_cfg, r_pipe, 
> r_pipe_cfg,
> -                                           pipe->sspp,
> -                                           
> msm_framebuffer_format(new_plane_state->fb),
> -                                           max_linewidth)) {
> -             DPU_DEBUG_PLANE(pdpu, "invalid " DRM_RECT_FMT " /" DRM_RECT_FMT
> -                             " max_line:%u, can't use split source\n",
> -                             DRM_RECT_ARG(&pipe_cfg->src_rect),
> -                             DRM_RECT_ARG(&r_pipe_cfg->src_rect),
> -                             max_linewidth);
> -             return -E2BIG;
> -     }
> -
> -     return dpu_plane_atomic_check_sspp(plane, state, crtc_state);
> +     /*
> +      * To trigger the callback of dpu_assign_plane_resources() to
> +      * finish the deferred sspp check
> +      */
> +     crtc_state->planes_changed = true;
> +     return 0;
>  }
>  
>  static int dpu_plane_virtual_atomic_check(struct drm_plane *plane,
> @@ -1186,10 +1162,6 @@ static int dpu_plane_virtual_atomic_check(struct 
> drm_plane *plane,
>       if (ret)
>               return ret;
>  
> -     ret = dpu_plane_split(plane, plane_state, crtc_state);
> -     if (ret)
> -             return ret;
> -
>       if (!plane_state->visible) {
>               /*
>                * resources are freed by dpu_crtc_assign_plane_resources(),
> @@ -1261,9 +1233,9 @@ static int dpu_plane_virtual_assign_resources(struct 
> drm_crtc *crtc,
>                                             struct dpu_global_state 
> *global_state,
>                                             struct drm_atomic_state *state,
>                                             struct drm_plane_state 
> *plane_state,
> +                                           const struct drm_crtc_state 
> *crtc_state,
>                                             struct drm_plane_state 
> **prev_adjacent_plane_state)
>  {
> -     const struct drm_crtc_state *crtc_state = NULL;
>       struct drm_plane *plane = plane_state->plane;
>       struct dpu_kms *dpu_kms = _dpu_plane_get_kms(plane);
>       struct dpu_rm_sspp_requirements reqs;
> @@ -1273,10 +1245,6 @@ static int dpu_plane_virtual_assign_resources(struct 
> drm_crtc *crtc,
>       const struct msm_format *fmt;
>       int i, ret;
>  
> -     if (plane_state->crtc)
> -             crtc_state = drm_atomic_get_new_crtc_state(state,
> -                                                        plane_state->crtc);
> -
>       pstate = to_dpu_plane_state(plane_state);
>       for (i = 0; i < STAGES_PER_PLANE; i++)
>               prev_adjacent_pstate[i] = prev_adjacent_plane_state[i] ?
> @@ -1288,6 +1256,10 @@ static int dpu_plane_virtual_assign_resources(struct 
> drm_crtc *crtc,
>       if (!plane_state->fb)
>               return -EINVAL;
>  
> +     ret = dpu_plane_split(plane, plane_state, crtc_state);
> +     if (ret)
> +             return ret;
> +
>       fmt = msm_framebuffer_format(plane_state->fb);
>       reqs.yuv = MSM_FORMAT_IS_YUV(fmt);
>       reqs.scale = (plane_state->src_w >> 16 != plane_state->crtc_w) ||
> @@ -1318,14 +1290,59 @@ static int dpu_plane_virtual_assign_resources(struct 
> drm_crtc *crtc,
>       return dpu_plane_atomic_check_sspp(plane, state, crtc_state);
>  }
>  
> +static int dpu_plane_assign_resources(struct drm_crtc *crtc,
> +                                   struct dpu_global_state *global_state,
> +                                   struct drm_atomic_state *state,
> +                                   struct drm_plane_state *plane_state,
> +                                   const struct drm_crtc_state *crtc_state,
> +                                   struct drm_plane_state 
> **prev_adjacent_plane_state)
> +{
> +     struct drm_plane *plane = plane_state->plane;
> +     struct dpu_kms *dpu_kms = _dpu_plane_get_kms(plane);
> +     struct dpu_plane_state *pstate = to_dpu_plane_state(plane_state);
> +     struct dpu_sw_pipe *pipe = &pstate->pipe[0];
> +     struct dpu_sw_pipe *r_pipe = &pstate->pipe[1];
> +     struct dpu_sw_pipe_cfg *pipe_cfg = &pstate->pipe_cfg[0];
> +     struct dpu_sw_pipe_cfg *r_pipe_cfg = &pstate->pipe_cfg[1];
> +     struct dpu_plane *pdpu = to_dpu_plane(plane);
> +     int ret;
> +
> +     if (!plane_state->visible)
> +             return 0;
> +
> +     pipe->sspp = dpu_rm_get_sspp(&dpu_kms->rm, pdpu->pipe);
> +     if (!pipe->sspp)
> +             return -EINVAL;
> +
> +     ret = dpu_plane_split(plane, plane_state, crtc_state);
> +     if (ret)
> +             return ret;
> +
> +     if (!dpu_plane_try_multirect_parallel(pipe, pipe_cfg, r_pipe, 
> r_pipe_cfg,
> +                                           pipe->sspp,
> +                                           
> msm_framebuffer_format(plane_state->fb),
> +                                           
> dpu_kms->catalog->caps->max_linewidth)) {
> +             DPU_DEBUG_PLANE(pdpu, "invalid " DRM_RECT_FMT " /" DRM_RECT_FMT
> +                             " max_line:%u, can't use split source\n",
> +                             DRM_RECT_ARG(&pipe_cfg->src_rect),
> +                             DRM_RECT_ARG(&r_pipe_cfg->src_rect),
> +                             dpu_kms->catalog->caps->max_linewidth);
> +             return -E2BIG;
> +     }
> +
> +     return dpu_plane_atomic_check_sspp(plane, state, crtc_state);
> +}
> +
>  int dpu_assign_plane_resources(struct dpu_global_state *global_state,
>                              struct drm_atomic_state *state,
>                              struct drm_crtc *crtc,
>                              struct drm_plane_state **states,
>                              unsigned int num_planes)
>  {
> -     unsigned int i;
>       struct drm_plane_state *prev_adjacent_plane_state[STAGES_PER_PLANE] = { 
> NULL };
> +     const struct drm_crtc_state *crtc_state = NULL;
> +     unsigned int i;
> +     int ret;
>  
>       for (i = 0; i < num_planes; i++) {
>               struct drm_plane_state *plane_state = states[i];
> @@ -1334,8 +1351,19 @@ int dpu_assign_plane_resources(struct dpu_global_state 
> *global_state,
>                   !plane_state->visible)
>                       continue;
>  
> -             int ret = dpu_plane_virtual_assign_resources(crtc, global_state,
> +             if (plane_state->crtc)
> +                     crtc_state = drm_atomic_get_new_crtc_state(state,
> +                                                                
> plane_state->crtc);
> +
> +             if (!dpu_use_virtual_planes)
> +                     ret = dpu_plane_assign_resources(crtc, global_state,
> +                                                      state, plane_state,
> +                                                      crtc_state,
> +                                                      
> prev_adjacent_plane_state);
> +             else
> +                     ret = dpu_plane_virtual_assign_resources(crtc, 
> global_state,
>                                                            state, plane_state,
> +                                                          crtc_state,
>                                                            
> prev_adjacent_plane_state);
>               if (ret)
>                       return ret;
> 
> -- 
> 2.43.0
> 

-- 
With best wishes
Dmitry

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