| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <6kzd2g4hgffqz5ipaqbourgiefuxxh3njj44n35blo37z6hhhj@us7lzlgmjuld>
Date: Wed, 21 Jan 2026 11:30:30 +0200
From: Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>
To: Jun Nie <jun.nie@...aro.org>
Cc: Abhinav Kumar <abhinav.kumar@...ux.dev>,
Dmitry Baryshkov <lumag@...nel.org>, Sean Paul <sean@...rly.run>,
Marijn Suijten <marijn.suijten@...ainline.org>,
David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>,
Rob Clark <robin.clark@....qualcomm.com>,
Neil Armstrong <neil.armstrong@...aro.org>,
linux-arm-msm@...r.kernel.org, dri-devel@...ts.freedesktop.org,
freedreno@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v17 2/4] drm/msm/dpu: Defer SSPP allocation until CRTC
check
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 <jun.nie@...aro.org>
> ---
> 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
Powered by blists - more mailing lists