Re: [REPOST PATCH v4 10/13] drm/msm/disp/dpu1: Add support for DSC in topology

Marijn Suijten
2022-02-17T21:44:25Z

On 2022-02-10 16:04:20, Vinod Koul wrote:
> For DSC to work we typically need a 2,2,1 configuration. This should
> suffice for resolutions up to 4k. For more resolutions like 8k this won't
> work.
>
> Also, it is better to use 2 LMs and DSC instances as half width results
> in lesser power consumption as compared to single LM, DSC at full width.
>
> The panel has been tested only with 2,2,1 configuration, so for
> now we blindly create 2,2,1 topology when DSC is enabled
>
> Co-developed-by: Abhinav Kumar <abhinavk@codeaurora.org>
> Signed-off-by: Abhinav Kumar <abhinavk@codeaurora.org>
> Signed-off-by: Vinod Koul <vkoul@kernel.org>
> ---
> drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c | 13 +++++++++++++
> drivers/gpu/drm/msm/msm_drv.h | 2 ++
> 2 files changed, 15 insertions(+)
>
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> index 95a7bf362e81..13ccb7b3cce5 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> @@ -574,8 +574,21 @@ static struct msm_display_topology dpu_encoder_get_topology(
> topology.num_enc = 0;
> topology.num_intf = intf_count;
>
> + if (dpu_enc->dsc) {
> + /* In case of Display Stream Compression DSC, we would use
> + * 2 encoders, 2 line mixers and 1 interface

LM is a layer mixer, not a line mixer, right?

- Marijn

> + * this is power optimal and can drive up to (including) 4k
> + * screens
> + */
> + topology.num_enc = 2;
> + topology.num_dsc = 2;
> + topology.num_intf = 1;
> + topology.num_lm = 2;
> + }
> +
> return topology;
> }
> +
> static int dpu_encoder_virt_atomic_check(
> struct drm_encoder *drm_enc,
> struct drm_crtc_state *crtc_state,
> diff --git a/drivers/gpu/drm/msm/msm_drv.h b/drivers/gpu/drm/msm/msm_drv.h
> index 6425a42e997c..994d895d1a47 100644
> --- a/drivers/gpu/drm/msm/msm_drv.h
> +++ b/drivers/gpu/drm/msm/msm_drv.h
> @@ -103,12 +103,14 @@ enum msm_event_wait {
> * @num_enc: number of compression encoder blocks used
> * @num_intf: number of interfaces the panel is mounted on
> * @num_dspp: number of dspp blocks used
> + * @num_dsc: number of Display Stream Compression (DSC) blocks used
> */
> struct msm_display_topology {
> u32 num_lm;
> u32 num_enc;
> u32 num_intf;
> u32 num_dspp;
> + u32 num_dsc;
> };
>
> /**
> --
> 2.31.1
>