[PATCH v9 13/14] drm/msm/dpu: support plane splitting in quad-pipe case

Jessica Zhang quic_jesszhan at quicinc.com
Thu May 8 21:24:50 UTC 2025



On 5/6/2025 8:47 AM, Jun Nie wrote:
> The content of every half of screen is sent out via one interface in
> dual-DSI case. The content for every interface is blended by a LM
> pair in quad-pipe case, thus a LM pair should not blend any content
> that cross the half of screen in this case. Clip plane into pipes per
> left and right half screen ROI if topology is quad pipe case.
> 
> The clipped rectangle on every half of screen is futher handled by two
> pipes if its width exceeds a limit for a single pipe.
> 
> Signed-off-by: Jun Nie <jun.nie at linaro.org>
> Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov at linaro.org>
> ---
>   drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c  |  11 +++
>   drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.h  |   2 +
>   drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c | 134 +++++++++++++++++++++---------
>   3 files changed, 107 insertions(+), 40 deletions(-)
> 
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
> index f35cb1f7a7d2c2c63b4228bc47b85bb57cddbe6b..a56d68de219910a827830293e8ff24f4cdee74e4 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
> @@ -1560,6 +1560,17 @@ int dpu_crtc_vblank(struct drm_crtc *crtc, bool en)
>   	return 0;
>   }
>   
> +/**
> + * dpu_crtc_get_num_lm - Get mixer number in this CRTC pipeline
> + * @state: Pointer to drm crtc state object
> + */
> +unsigned int dpu_crtc_get_num_lm(const struct drm_crtc_state *state)
> +{
> +	struct dpu_crtc_state *cstate = to_dpu_crtc_state(state);
> +
> +	return cstate->num_mixers;
> +}
> +
>   #ifdef CONFIG_DEBUG_FS
>   static int _dpu_debugfs_status_show(struct seq_file *s, void *data)
>   {
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.h b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.h
> index 94392b9b924546f96e738ae20920cf9afd568e6b..6eaba5696e8e6bd1246a9895c4c8714ca6589b10 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.h
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.h
> @@ -267,4 +267,6 @@ static inline enum dpu_crtc_client_type dpu_crtc_get_client_type(
>   
>   void dpu_crtc_frame_event_cb(struct drm_crtc *crtc, u32 event);
>   
> +unsigned int dpu_crtc_get_num_lm(const struct drm_crtc_state *state);
> +
>   #endif /* _DPU_CRTC_H_ */
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c
> index de3f52d743e1d1f11ae8721a316b9872d4139069..cf2b4d5cb0ccc144c2cf8fd227c862b0b6e7725f 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c
> @@ -831,8 +831,12 @@ static int dpu_plane_atomic_check_nosspp(struct drm_plane *plane,
>   	struct dpu_plane_state *pstate = to_dpu_plane_state(new_plane_state);
>   	struct dpu_sw_pipe_cfg *pipe_cfg;
>   	struct dpu_sw_pipe_cfg *r_pipe_cfg;
> +	struct dpu_sw_pipe_cfg init_pipe_cfg;
>   	struct drm_rect fb_rect = { 0 };
> +	const struct drm_display_mode *mode = &crtc_state->adjusted_mode;
>   	uint32_t max_linewidth;
> +	u32 num_lm;
> +	int stage_id, num_stages;
>   
>   	min_scale = FRAC_16_16(1, MAX_UPSCALE_RATIO);
>   	max_scale = MAX_DOWNSCALE_RATIO << 16;
> @@ -855,13 +859,10 @@ static int dpu_plane_atomic_check_nosspp(struct drm_plane *plane,
>   		return -EINVAL;
>   	}
>   
> -	/* move the assignment here, to ease handling to another pairs later */
> -	pipe_cfg = &pstate->pipe_cfg[0];
> -	r_pipe_cfg = &pstate->pipe_cfg[1];
> -	/* state->src is 16.16, src_rect is not */
> -	drm_rect_fp_to_int(&pipe_cfg->src_rect, &new_plane_state->src);
> +	num_lm = dpu_crtc_get_num_lm(crtc_state);
>   
> -	pipe_cfg->dst_rect = new_plane_state->dst;
> +	/* state->src is 16.16, src_rect is not */
> +	drm_rect_fp_to_int(&init_pipe_cfg.src_rect, &new_plane_state->src);
>   
>   	fb_rect.x2 = new_plane_state->fb->width;
>   	fb_rect.y2 = new_plane_state->fb->height;
> @@ -886,35 +887,91 @@ static int dpu_plane_atomic_check_nosspp(struct drm_plane *plane,
>   
>   	max_linewidth = pdpu->catalog->caps->max_linewidth;
>   
> -	drm_rect_rotate(&pipe_cfg->src_rect,
> +	drm_rect_rotate(&init_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) ||
> -	     _dpu_plane_calc_clk(&crtc_state->adjusted_mode, pipe_cfg) > max_mdp_clk_rate) {
> -		if (drm_rect_width(&pipe_cfg->src_rect) > 2 * max_linewidth) {
> -			DPU_DEBUG_PLANE(pdpu, "invalid src " DRM_RECT_FMT " line:%u\n",
> -					DRM_RECT_ARG(&pipe_cfg->src_rect), max_linewidth);
> -			return -E2BIG;
> +	/*
> +	 * We have 1 mixer pair cfg for 1:1:1 and 2:2:1 topology, 2 mixer pair
> +	 * configs for left and right half screen in case of 4:4:2 topology.
> +	 * But we may have 2 rect to split wide plane that exceeds limit with 1
> +	 * config for 2:2:1. So need to handle both wide plane splitting, and
> +	 * two halves of screen splitting for quad-pipe case. Check dest
> +	 * rectangle left/right clipping first, then check wide rectangle
> +	 * splitting in every half next.
> +	 */
> +	num_stages = (num_lm + 1) / 2;
> +	/* iterate mixer configs for this plane, to separate left/right with the id */
> +	for (stage_id = 0; stage_id < num_stages; stage_id++) {
> +		struct drm_rect mixer_rect = {stage_id * mode->hdisplay / num_stages, 0,
> +					(stage_id + 1) * mode->hdisplay / num_stages,
> +					mode->vdisplay};

Hi Jun,

Nit: can you specify the fields when initializing the drm_rect struct here?

e.g.:

mixer_rect = {
	.x1 = ...,
	.y1 = ...
	...
}

> +		int cfg_idx = stage_id * PIPES_PER_STAGE;
> +
> +		pipe_cfg = &pstate->pipe_cfg[cfg_idx];
> +		r_pipe_cfg = &pstate->pipe_cfg[cfg_idx + 1];
> +
> +		drm_rect_fp_to_int(&pipe_cfg->src_rect, &new_plane_state->src);
> +		pipe_cfg->dst_rect = new_plane_state->dst;
> +
> +		DPU_DEBUG_PLANE(pdpu, "checking src " DRM_RECT_FMT
> +				" vs clip window " DRM_RECT_FMT "\n",
> +				DRM_RECT_ARG(&pipe_cfg->src_rect),
> +				DRM_RECT_ARG(&mixer_rect));
> +
> +		/*
> +		 * If this plane does not fall into mixer rect, check next
> +		 * mixer rect.
> +		 */
> +		if (!drm_rect_clip_scaled(&pipe_cfg->src_rect,
> +					  &pipe_cfg->dst_rect,
> +					  &mixer_rect)) {
> +			memset(pipe_cfg, 0, 2 * sizeof(struct dpu_sw_pipe_cfg));
> +
> +			continue;
>   		}
>   
> -		*r_pipe_cfg = *pipe_cfg;
> -		pipe_cfg->src_rect.x2 = (pipe_cfg->src_rect.x1 + pipe_cfg->src_rect.x2) >> 1;
> -		pipe_cfg->dst_rect.x2 = (pipe_cfg->dst_rect.x1 + pipe_cfg->dst_rect.x2) >> 1;
> -		r_pipe_cfg->src_rect.x1 = pipe_cfg->src_rect.x2;
> -		r_pipe_cfg->dst_rect.x1 = pipe_cfg->dst_rect.x2;
> -	} else {
> -		memset(r_pipe_cfg, 0, sizeof(*r_pipe_cfg));
> -	}
> +		pipe_cfg->dst_rect.x1 -= mixer_rect.x1;
> +		pipe_cfg->dst_rect.x2 -= mixer_rect.x1;
> +
> +		DPU_DEBUG_PLANE(pdpu, "Got clip src:" DRM_RECT_FMT " dst: " DRM_RECT_FMT "\n",
> +				DRM_RECT_ARG(&pipe_cfg->src_rect), DRM_RECT_ARG(&pipe_cfg->dst_rect));
>   
> -	drm_rect_rotate_inv(&pipe_cfg->src_rect,
> -			    new_plane_state->fb->width, new_plane_state->fb->height,
> -			    new_plane_state->rotation);
> -	if (drm_rect_width(&r_pipe_cfg->src_rect) != 0)
> -		drm_rect_rotate_inv(&r_pipe_cfg->src_rect,
> -				    new_plane_state->fb->width, new_plane_state->fb->height,
> +		/* Split wide rect into 2 rect */
> +		if ((drm_rect_width(&pipe_cfg->src_rect) > max_linewidth) ||
> +		     _dpu_plane_calc_clk(mode, pipe_cfg) > max_mdp_clk_rate) {
> +
> +			if (drm_rect_width(&pipe_cfg->src_rect) > 2 * max_linewidth) {
> +				DPU_DEBUG_PLANE(pdpu, "invalid src " DRM_RECT_FMT " line:%u\n",
> +						DRM_RECT_ARG(&pipe_cfg->src_rect), max_linewidth);
> +				return -E2BIG;
> +			}
> +
> +			memcpy(r_pipe_cfg, pipe_cfg, sizeof(struct dpu_sw_pipe_cfg));
> +			pipe_cfg->src_rect.x2 = (pipe_cfg->src_rect.x1 + pipe_cfg->src_rect.x2) >> 1;
> +			pipe_cfg->dst_rect.x2 = (pipe_cfg->dst_rect.x1 + pipe_cfg->dst_rect.x2) >> 1;
> +			r_pipe_cfg->src_rect.x1 = pipe_cfg->src_rect.x2;
> +			r_pipe_cfg->dst_rect.x1 = pipe_cfg->dst_rect.x2;
> +			DPU_DEBUG_PLANE(pdpu, "Split wide plane into:"
> +					DRM_RECT_FMT " and " DRM_RECT_FMT "\n",
> +					DRM_RECT_ARG(&pipe_cfg->src_rect),
> +					DRM_RECT_ARG(&r_pipe_cfg->src_rect));
> +		} else {
> +			memset(r_pipe_cfg, 0, sizeof(struct dpu_sw_pipe_cfg));
> +		}
> +
> +		drm_rect_rotate_inv(&pipe_cfg->src_rect,
> +				    new_plane_state->fb->width,
> +				    new_plane_state->fb->height,
>   				    new_plane_state->rotation);
>   
> +		if (drm_rect_width(&r_pipe_cfg->src_rect) != 0)
> +			drm_rect_rotate_inv(&r_pipe_cfg->src_rect,
> +					    new_plane_state->fb->width,
> +					    new_plane_state->fb->height,
> +					    new_plane_state->rotation);
> +	}
> +
>   	pstate->needs_qos_remap = drm_atomic_crtc_needs_modeset(crtc_state);
>   
>   	return 0;
> @@ -954,20 +1011,17 @@ static int dpu_plane_atomic_check_sspp(struct drm_plane *plane,
>   		drm_atomic_get_new_plane_state(state, plane);
>   	struct dpu_plane *pdpu = to_dpu_plane(plane);
>   	struct dpu_plane_state *pstate = to_dpu_plane_state(new_plane_state);
> -	struct dpu_sw_pipe *pipe = &pstate->pipe[0];
> -	struct dpu_sw_pipe *r_pipe = &pstate->pipe[1];
> -	struct dpu_sw_pipe_cfg *pipe_cfg = &pstate->pipe_cfg[0];
> -	struct dpu_sw_pipe_cfg *r_pipe_cfg = &pstate->pipe_cfg[1];
> -	int ret = 0;
> -
> -	ret = dpu_plane_atomic_check_pipe(pdpu, pipe, pipe_cfg,
> -					  &crtc_state->adjusted_mode,
> -					  new_plane_state);
> -	if (ret)
> -		return ret;
> +	struct dpu_sw_pipe *pipe;
> +	struct dpu_sw_pipe_cfg *pipe_cfg;
> +	int ret = 0, i;
>   
> -	if (drm_rect_width(&r_pipe_cfg->src_rect) != 0) {

Any reason why this check was dropped?

Thanks,

Jessica Zhang

> -		ret = dpu_plane_atomic_check_pipe(pdpu, r_pipe, r_pipe_cfg,
> +	for (i = 0; i < PIPES_PER_PLANE; i++) {
> +		pipe = &pstate->pipe[i];
> +		pipe_cfg = &pstate->pipe_cfg[i];
> +		if (!pipe->sspp)
> +			continue;
> +		DPU_DEBUG_PLANE(pdpu, "pipe %d is in use, validate it\n", i);
> +		ret = dpu_plane_atomic_check_pipe(pdpu, pipe, pipe_cfg,
>   						  &crtc_state->adjusted_mode,
>   						  new_plane_state);
>   		if (ret)
> 



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