linux-kernel - Re: [PATCH v6 13/15] drm/msm/dpu: support SSPP assignment for quad-pipe case

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

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <n22g66ruabunma4w4p44zjtsnb5t4vdpjuaocasbup3alb4fxp@74tu3wnqbwfg>
Date: Mon, 24 Feb 2025 19:08:06 +0200
From: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To: Jun Nie <jun.nie@...aro.org>
Cc: Rob Clark <robdclark@...il.com>, 
	Abhinav Kumar <quic_abhinavk@...cinc.com>, Sean Paul <sean@...rly.run>, 
	Marijn Suijten <marijn.suijten@...ainline.org>, David Airlie <airlied@...il.com>, 
	Simona Vetter <simona@...ll.ch>, Jessica Zhang <quic_jesszhan@...cinc.com>, 
	linux-arm-msm@...r.kernel.org, dri-devel@...ts.freedesktop.org, freedreno@...ts.freedesktop.org, 
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v6 13/15] drm/msm/dpu: support SSPP assignment for
 quad-pipe case

On Mon, Feb 24, 2025 at 06:14:22PM +0800, Jun Nie wrote:
> Dmitry Baryshkov <dmitry.baryshkov@...aro.org> 于2025年2月22日周六 00:36写道：
> >
> > On Mon, Feb 17, 2025 at 10:16:02PM +0800, Jun Nie wrote:
> > > Currently, SSPPs are assigned to a maximum of two pipes. However,
> > > quad-pipe usage scenarios require four pipes and involve configuring
> > > two stages. In quad-pipe case, the first two pipes share a set of
> > > mixer configurations and enable multi-rect mode when certain
> > > conditions are met. The same applies to the subsequent two pipes.
> > >
> > > Assign SSPPs to the pipes in each stage using a unified method and
> > > to loop the stages accordingly.
> > >
> > > Signed-off-by: Jun Nie <jun.nie@...aro.org>
> > > ---
> > >  drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c | 63 +++++++++++++++++++------------
> > >  1 file changed, 39 insertions(+), 24 deletions(-)
> > >
> > > +     for (stage_id = 0; stage_id < num_stages; stage_id++) {
> > > +             for (i = stage_id * PIPES_PER_STAGE; i < (stage_id + 1) * PIPES_PER_STAGE; i++) {
> 
> Do you mean define and assign r_pipe / r_pipe_cfg here?

No, because for i = num_stages-1, the r_pipe would point to invalid
memory.

> 
> > > +                     pipe = &pstate->pipe[i];
> > > +                     pipe_cfg = &pstate->pipe_cfg[i];
> > > +
> > > +                     if (drm_rect_width(&pipe_cfg->src_rect) == 0)
> > > +                             break;
> > > +
> > > +                     pipe->sspp = dpu_rm_reserve_sspp(&dpu_kms->rm, global_state, crtc, &reqs);
> > > +                     if (!pipe->sspp)
> > > +                             return -ENODEV;
> > > +
> > > +                     r_pipe = &pstate->pipe[i + 1];
> > > +                     r_pipe_cfg = &pstate->pipe_cfg[i + 1];
> > > +
> > > +                     /*
> > > +                      * If current pipe is the first pipe in pipe pair, check
> > > +                      * multi-rect opportunity for the 2nd pipe in the pair.
> > > +                      * SSPP multi-rect mode cross mixer pairs is not supported.
> > > +                      */
> > > +                     if ((i % PIPES_PER_STAGE == 0) &&
> >
> > Please move r_pipe / r_pipe_cfg definition and assignment here.
> 
> r_pipe / r_pipe_cfg is used in this if(). Please see above question.

Maybe we can rework it somehow. I really don't fancy the after-the-array
pointer.

> >
> >
> > > +                         drm_rect_width(&r_pipe_cfg->src_rect) != 0 &&
> > > +                         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)) {
> > > +                             i++;
> > > +                     } else {
> > > +                             /* multirect is not possible, use two SSPP blocks */
> > > +                             pipe->multirect_index = DPU_SSPP_RECT_SOLO;
> > > +                             pipe->multirect_mode = DPU_SSPP_MULTIRECT_NONE;
> > > +                             DPU_DEBUG_PLANE(pdpu, "allocating sspp_%d for pipe %d.\n",
> > > +                                             pipe->sspp->idx - SSPP_NONE, i);
> > > +                     }
> > > +             }
> > >       }
> > >
> > >       return dpu_plane_atomic_check_sspp(plane, state, crtc_state);
> > >
> > > --
> > > 2.34.1
> > >
> >
> > --
> > With best wishes
> > Dmitry

-- 
With best wishes
Dmitry