[PATCH v18 2/4] drm/msm/dpu: Defer SSPP allocation until CRTC check

From: Jun Nie

Date: Fri Feb 13 2026 - 09:58:49 EST


Currently, mapping plane to SSPP occurs during the plane check phase for
non-virtual plane case. The SSPP allocation and plane mapping occurs during
crtc check phase for virtual plane case. Defer these SSPP operations until
CRTC check stage to unify the 2 cases, and ease later revisement for
quad-pipe change.

Signed-off-by: Jun Nie <jun.nie@xxxxxxxxxx>
---
drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c | 3 +-
drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c | 155 +++++++++++++-----------------
2 files changed, 66 insertions(+), 92 deletions(-)

diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
index 6bf7c46379aed..797296b14264e 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
@@ -1534,8 +1534,7 @@ 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..be1a7fcf11b81 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c
@@ -1119,102 +1119,24 @@ 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);
-}
-
-static int dpu_plane_virtual_atomic_check(struct drm_plane *plane,
- struct drm_atomic_state *state)
-{
- struct drm_plane_state *plane_state =
- drm_atomic_get_plane_state(state, plane);
- struct drm_plane_state *old_plane_state =
- drm_atomic_get_old_plane_state(state, plane);
- struct dpu_plane_state *pstate = to_dpu_plane_state(plane_state);
- struct drm_crtc_state *crtc_state = NULL;
- int ret, i;
-
- if (IS_ERR(plane_state))
- return PTR_ERR(plane_state);
-
- if (plane_state->crtc)
- crtc_state = drm_atomic_get_new_crtc_state(state,
- plane_state->crtc);
-
- ret = dpu_plane_atomic_check_nosspp(plane, plane_state, crtc_state);
- 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(),
- * but clean them here.
- */
- for (i = 0; i < PIPES_PER_PLANE; i++)
- pstate->pipe[i].sspp = NULL;
-
- return 0;
- }
-
/*
- * Force resource reallocation if the format of FB or src/dst have
- * changed. We might need to allocate different SSPP or SSPPs for this
- * plane than the one used previously.
+ * To trigger the callback of dpu_assign_plane_resources() to
+ * finish the sspp assignment or allocation and check.
*/
- if (!old_plane_state || !old_plane_state->fb ||
- old_plane_state->src_w != plane_state->src_w ||
- old_plane_state->src_h != plane_state->src_h ||
- old_plane_state->crtc_w != plane_state->crtc_w ||
- old_plane_state->crtc_h != plane_state->crtc_h ||
- msm_framebuffer_format(old_plane_state->fb) !=
- msm_framebuffer_format(plane_state->fb))
- crtc_state->planes_changed = true;
-
+ crtc_state->planes_changed = true;
return 0;
}

@@ -1261,9 +1183,9 @@ 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 +1195,6 @@ 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 +1206,10 @@ 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 +1240,56 @@ 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;
+
+ 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 +1298,19 @@ 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;
@@ -1772,7 +1747,7 @@ static const struct drm_plane_helper_funcs dpu_plane_helper_funcs = {
static const struct drm_plane_helper_funcs dpu_plane_virtual_helper_funcs = {
.prepare_fb = dpu_plane_prepare_fb,
.cleanup_fb = dpu_plane_cleanup_fb,
- .atomic_check = dpu_plane_virtual_atomic_check,
+ .atomic_check = dpu_plane_atomic_check,
.atomic_update = dpu_plane_atomic_update,
};


--
2.43.0