[PATCH] drm/amd/display: Keep linebuffer pixel depth at 30bpp for DCE-11.0.

[Alex Deucher]

Applied.  Thanks!

Alex

On Wed, Jun 2, 2021 at 4:58 PM Harry Wentland <harry.wentland at amd.com> wrote:
>
> On 2021-06-02 4:45 p.m., Mario Kleiner wrote:
> > Testing on AMD Carizzo with DCE-11.0 display engine showed that
> > it doesn't like a 36 bpp linebuffer very much. The display just
> > showed a solid green.
> >
> > Testing on RavenRidge DCN-1.0, Polaris11 with DCE-11.2 and Kabini
> > with DCE-8.3 did not expose any problems, so for now only revert
> > to 30 bpp linebuffer depth on asics with DCE-11.0 display engine.
> >
> > Reported-by: Tom StDenis <Tom.StDenis at amd.com>
> > Signed-off-by: Mario Kleiner <mario.kleiner.de at gmail.com>
> > Cc: Alex Deucher <alexander.deucher at amd.com>
>
> Curious now why Carrizo doesn't like a LB depth of 36bpp but
> this should fix the issue.
>
> Reviewed-by: Harry Wentland <harry.wentland at amd.com>
>
> Harry
>
> > ---
> >  drivers/gpu/drm/amd/display/dc/core/dc_resource.c | 11 +++++++++--
> >  1 file changed, 9 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_resource.c b/drivers/gpu/drm/amd/display/dc/core/dc_resource.c
> > index b2ee3cd77b4e..a4f1ae8930a4 100644
> > --- a/drivers/gpu/drm/amd/display/dc/core/dc_resource.c
> > +++ b/drivers/gpu/drm/amd/display/dc/core/dc_resource.c
> > @@ -1213,9 +1213,16 @@ bool resource_build_scaling_params(struct pipe_ctx *pipe_ctx)
> >        * on certain displays, such as the Sharp 4k. 36bpp is needed
> >        * to support SURFACE_PIXEL_FORMAT_GRPH_ARGB16161616 and
> >        * SURFACE_PIXEL_FORMAT_GRPH_ABGR16161616 with actual > 10 bpc
> > -      * precision on at least DCN display engines.
> > +      * precision on at least DCN display engines. However, at least
> > +      * Carrizo with DCE_VERSION_11_0 does not like 36 bpp lb depth,
> > +      * so use only 30 bpp on DCE_VERSION_11_0. Testing with DCE 11.2 and 8.3
> > +      * did not show such problems, so this seems to be the exception.
> >        */
> > -     pipe_ctx->plane_res.scl_data.lb_params.depth = LB_PIXEL_DEPTH_36BPP;
> > +     if (plane_state->ctx->dce_version != DCE_VERSION_11_0)
> > +             pipe_ctx->plane_res.scl_data.lb_params.depth = LB_PIXEL_DEPTH_36BPP;
> > +     else
> > +             pipe_ctx->plane_res.scl_data.lb_params.depth = LB_PIXEL_DEPTH_30BPP;
> > +
> >       pipe_ctx->plane_res.scl_data.lb_params.alpha_en = plane_state->per_pixel_alpha;
> >
> >       pipe_ctx->plane_res.scl_data.recout.x += timing->h_border_left;
> >
>
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