Messages in this thread | | | Date | Wed, 30 Mar 2022 08:30:23 -0400 | Subject | Re: [PATCH v2] drm/amd/display: don't ignore alpha property on pre-multiplied mode | From | Rodrigo Siqueira Jordao <> |
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On 2022-03-29 16:18, Melissa Wen wrote: > "Pre-multiplied" is the default pixel blend mode for KMS/DRM, as > documented in supported_modes of drm_plane_create_blend_mode_property(): > https://cgit.freedesktop.org/drm/drm-misc/tree/drivers/gpu/drm/drm_blend.c > > In this mode, both 'pixel alpha' and 'plane alpha' participate in the > calculation, as described by the pixel blend mode formula in KMS/DRM > documentation: > > out.rgb = plane_alpha * fg.rgb + > (1 - (plane_alpha * fg.alpha)) * bg.rgb > > Considering the blend config mechanisms we have in the driver so far, > the alpha mode that better fits this blend mode is the > _PER_PIXEL_ALPHA_COMBINED_GLOBAL_GAIN, where the value for global_gain > is the plane alpha (global_alpha). > > With this change, alpha property stops to be ignored. It also addresses > Bug: https://gitlab.freedesktop.org/drm/amd/-/issues/1734 > > v2: > * keep the 8-bit value for global_alpha_value (Nicholas) > * correct the logical ordering for combined global gain (Nicholas) > * apply to dcn10 too (Nicholas) > > Signed-off-by: Melissa Wen <mwen@igalia.com> > --- > .../drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c | 14 +++++++++----- > drivers/gpu/drm/amd/display/dc/dcn20/dcn20_hwseq.c | 14 +++++++++----- > 2 files changed, 18 insertions(+), 10 deletions(-) > > diff --git a/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c b/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c > index ad757b59e00e..b1034e6258c8 100644 > --- a/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c > +++ b/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c > @@ -2528,14 +2528,18 @@ void dcn10_update_mpcc(struct dc *dc, struct pipe_ctx *pipe_ctx) > struct mpc *mpc = dc->res_pool->mpc; > struct mpc_tree *mpc_tree_params = &(pipe_ctx->stream_res.opp->mpc_tree_params); > > - if (per_pixel_alpha) > - blnd_cfg.alpha_mode = MPCC_ALPHA_BLEND_MODE_PER_PIXEL_ALPHA; > - else > - blnd_cfg.alpha_mode = MPCC_ALPHA_BLEND_MODE_GLOBAL_ALPHA; > - > blnd_cfg.overlap_only = false; > blnd_cfg.global_gain = 0xff; > > + if (per_pixel_alpha && pipe_ctx->plane_state->global_alpha) { > + blnd_cfg.alpha_mode = MPCC_ALPHA_BLEND_MODE_PER_PIXEL_ALPHA_COMBINED_GLOBAL_GAIN; > + blnd_cfg.global_gain = pipe_ctx->plane_state->global_alpha_value; > + } else if (per_pixel_alpha) { > + blnd_cfg.alpha_mode = MPCC_ALPHA_BLEND_MODE_PER_PIXEL_ALPHA; > + } else { > + blnd_cfg.alpha_mode = MPCC_ALPHA_BLEND_MODE_GLOBAL_ALPHA; > + } > + > if (pipe_ctx->plane_state->global_alpha) > blnd_cfg.global_alpha = pipe_ctx->plane_state->global_alpha_value; > else > diff --git a/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_hwseq.c b/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_hwseq.c > index 4290eaf11a04..b627c41713cc 100644 > --- a/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_hwseq.c > +++ b/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_hwseq.c > @@ -2344,14 +2344,18 @@ void dcn20_update_mpcc(struct dc *dc, struct pipe_ctx *pipe_ctx) > struct mpc *mpc = dc->res_pool->mpc; > struct mpc_tree *mpc_tree_params = &(pipe_ctx->stream_res.opp->mpc_tree_params); > > - if (per_pixel_alpha) > - blnd_cfg.alpha_mode = MPCC_ALPHA_BLEND_MODE_PER_PIXEL_ALPHA; > - else > - blnd_cfg.alpha_mode = MPCC_ALPHA_BLEND_MODE_GLOBAL_ALPHA; > - > blnd_cfg.overlap_only = false; > blnd_cfg.global_gain = 0xff; > > + if (per_pixel_alpha && pipe_ctx->plane_state->global_alpha) { > + blnd_cfg.alpha_mode = MPCC_ALPHA_BLEND_MODE_PER_PIXEL_ALPHA_COMBINED_GLOBAL_GAIN; > + blnd_cfg.global_gain = pipe_ctx->plane_state->global_alpha_value; > + } else if (per_pixel_alpha) { > + blnd_cfg.alpha_mode = MPCC_ALPHA_BLEND_MODE_PER_PIXEL_ALPHA; > + } else { > + blnd_cfg.alpha_mode = MPCC_ALPHA_BLEND_MODE_GLOBAL_ALPHA; > + } > +
Hi Melissa,
Thanks a lot for this patch. I run your patch in our CI, and everything looks good from the IGT test result.
In this sense: Tested-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
However, I think it is still necessary to have someone else review.
Harry, Nick, or Zhan, what do you think about this change?
Thanks Siqueira
> if (pipe_ctx->plane_state->global_alpha) > blnd_cfg.global_alpha = pipe_ctx->plane_state->global_alpha_value; > else
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