[RFC PATCH v2 02/13] drm/msm/dpu: take plane rotation into account for wide planes

[Dmitry Baryshkov]

On Mon, 15 May 2023 at 21:45, Abhinav Kumar <quic_abhinavk at quicinc.com> wrote:
>
>
>
> On 5/14/2023 10:01 AM, Dmitry Baryshkov wrote:
> > On Sat, 13 May 2023 at 01:12, Abhinav Kumar <quic_abhinavk at quicinc.com> wrote:
> >>
> >>
> >>
> >> On 3/20/2023 6:18 PM, Dmitry Baryshkov wrote:
> >>> Take into account the plane rotation and flipping when calculating src
> >>> positions for the wide plane parts.
> >>>
> >>> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov at linaro.org>
> >>
> >> Do we need to have a fixes tag for this? This means we dont consider
> >> rotation while calculating src position today which is a bug?
> >
> > Hmm, I thought that I had a check forbidding rotation with the current
> > approach, but I don't see it. Most probably I thought about it and
> > then forgot to add it.
> > The proper fix should be to disallow it for static SSPP case. I'll
> > include the patch into v3.
> >
> >>
> >>> ---
> >>>    drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c | 27 ++++++++++++++---------
> >>>    1 file changed, 17 insertions(+), 10 deletions(-)
> >>>
> >>> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c
> >>> index 2e63eb0a2f3f..d43e04fc4578 100644
> >>> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c
> >>> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c
> >>> @@ -887,16 +887,6 @@ static int dpu_plane_atomic_check(struct drm_plane *plane,
> >>>                return -EINVAL;
> >>>        }
> >>>
> >>> -     pipe_cfg->src_rect = new_plane_state->src;
> >>> -
> >>> -     /* state->src is 16.16, src_rect is not */
> >>> -     pipe_cfg->src_rect.x1 >>= 16;
> >>> -     pipe_cfg->src_rect.x2 >>= 16;
> >>> -     pipe_cfg->src_rect.y1 >>= 16;
> >>> -     pipe_cfg->src_rect.y2 >>= 16;
> >>> -
> >>> -     pipe_cfg->dst_rect = new_plane_state->dst;
> >>> -
> >>>        fb_rect.x2 = new_plane_state->fb->width;
> >>>        fb_rect.y2 = new_plane_state->fb->height;
> >>>
> >>> @@ -912,6 +902,15 @@ static int dpu_plane_atomic_check(struct drm_plane *plane,
> >>>
> >>>        max_linewidth = pdpu->catalog->caps->max_linewidth;
> >>>
> >>> +     /* state->src is 16.16, src_rect is not */
> >>> +     drm_rect_fp_to_int(&pipe_cfg->src_rect, &new_plane_state->src);
> >>> +
> >>> +     pipe_cfg->dst_rect = new_plane_state->dst;
> >>> +
> >>> +     drm_rect_rotate(&pipe_cfg->src_rect,
> >>> +                     new_plane_state->fb->width, new_plane_state->fb->height,
> >>> +                     new_plane_state->rotation);
> >>> +
> >>>        if (drm_rect_width(&pipe_cfg->src_rect) > max_linewidth) {
> >>>                /*
> >>>                 * In parallel multirect case only the half of the usual width
> >>> @@ -959,6 +958,14 @@ static int dpu_plane_atomic_check(struct drm_plane *plane,
> >>>                r_pipe_cfg->dst_rect.x1 = pipe_cfg->dst_rect.x2;
> >>>        }
> >>>
> >>> +     drm_rect_rotate_inv(&pipe_cfg->src_rect,
> >>> +                         new_plane_state->fb->width, new_plane_state->fb->height,
> >>> +                         new_plane_state->rotation);
> >>> +     if (r_pipe->sspp)
> >>
> >> Dont you need to check for if (r_pipe_cfg) here and not if
> >> (r_pipe->sspp) because parameter you are passing is the r_pipe_cfg to
> >> drm_rect_rotate_inv().
> >
> > Of course not. r_pipe_cfg is a pointer to the field in pstate. We know
> > that it can not be NULL.
> >
>
> Ack, and my bad for not checking that r_pipe_cfg points to a field in
> pstate but .... it was just weird though that you are checking for
> r_pipe->sspp before calling a method which really doesnt care if its
> null or not. How about you use drm_rect_visible(r_pipe_cfg->src_rect)
>
> If its not set, it wont be visible too.

I think it is better for the uniformity to check for r_pipe->sspp:
this is the condition that is used all over the driver to check that
r_pipe is used.

>
> >>
> >> So we rotated the pipe_cfg once, then rotated_inv it to restore the
> >> rectangle to its original state, but r_pipe_cfg's rectangle was never
> >> rotated as it was not allocated before this function so it will remain
> >> in inverse rotated state now right?
> >
> > No. r_pipe_cfg is set beforehand to the half of the rotated pipe_cfg.
> >
>
> Ok i got it now. Instead of directly operating on the plane_state's
> rectangle which makes you to invert again why not just use a temporary
> drm_rect which stores the rotated pipe_cfg->src_rect. That way you dont
> have to invert anything?

I don't think this will work. I explicitly rotate & invert rotation to
get correct coordinates for both source and destination rectangles.
Doing it otherwise would require us to manually implement this in the
DPU driver.

>
> >>> +             drm_rect_rotate_inv(&r_pipe_cfg->src_rect,
> >>> +                                 new_plane_state->fb->width, new_plane_state->fb->height,
> >>> +                                 new_plane_state->rotation);
> >>> +
> >>>        ret = dpu_plane_atomic_check_pipe(pdpu, pipe, pipe_cfg, fmt);
> >>>        if (ret)
> >>>                return ret;
> >
> >
> >
> > --
> > With best wishes
> > Dmitry



-- 
With best wishes
Dmitry