linux-kernel - Re: [PATCH v5 08/15] drm/msm/dpu: bind correct pingpong for quad pipe

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Message-ID: <6n655caflr2snsgmqtmpzxt4jynrwjqdjurnixujfuefldxhxj@uunzpzfezfqy>
Date: Mon, 20 Jan 2025 14:15:13 +0100
From: Marijn Suijten <marijn.suijten@...ainline.org>
To: Jun Nie <jun.nie@...aro.org>
Cc: Rob Clark <robdclark@...il.com>, 
	Abhinav Kumar <quic_abhinavk@...cinc.com>, Dmitry Baryshkov <dmitry.baryshkov@...aro.org>, 
	Sean Paul <sean@...rly.run>, David Airlie <airlied@...il.com>, 
	Simona Vetter <simona@...ll.ch>, linux-arm-msm@...r.kernel.org, dri-devel@...ts.freedesktop.org, 
	freedreno@...ts.freedesktop.org, linux-kernel@...r.kernel.org, 
	Jessica Zhang <quic_jesszhan@...cinc.com>
Subject: Re: [PATCH v5 08/15] drm/msm/dpu: bind correct pingpong for quad pipe

On 2025-01-18 00:00:51, Jun Nie wrote:
> There are 2 interfaces and 4 pingpong in quad pipe. Map the 2nd
> interface to 3rd PP instead of the 2nd PP.

Can you explain why this patch uses the number of LMs, instead of dividing the
number of PPs divided by the number of physical encoders?  This detail is not
explained at all, or that we're filling hw_lm now for no other reason.

- Marijn

> Signed-off-by: Jun Nie <jun.nie@...aro.org>
> Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
> Reviewed-by: Jessica Zhang <quic_jesszhan@...cinc.com>
> ---
>  drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c | 15 +++++++++++++--
>  1 file changed, 13 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> index 018a1a49ca7d1..b0cab3ccbb57c 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> @@ -1220,7 +1220,8 @@ static void dpu_encoder_virt_atomic_mode_set(struct drm_encoder *drm_enc,
>  	struct dpu_hw_blk *hw_pp[MAX_CHANNELS_PER_ENC];
>  	struct dpu_hw_blk *hw_ctl[MAX_CHANNELS_PER_ENC];
>  	struct dpu_hw_blk *hw_dsc[MAX_CHANNELS_PER_ENC];
> -	int num_ctl, num_pp, num_dsc;
> +	struct dpu_hw_blk *hw_lm[MAX_CHANNELS_PER_ENC];
> +	int num_lm, num_ctl, num_pp, num_dsc, num_pp_per_intf;
>  	unsigned int dsc_mask = 0;
>  	int i;
>  
> @@ -1275,11 +1276,21 @@ static void dpu_encoder_virt_atomic_mode_set(struct drm_encoder *drm_enc,
>  		dpu_enc->cur_master->hw_cdm = hw_cdm ? to_dpu_hw_cdm(hw_cdm) : NULL;
>  	}
>  
> +	num_lm = dpu_rm_get_assigned_resources(&dpu_kms->rm, global_state,
> +		drm_enc->crtc, DPU_HW_BLK_LM, hw_lm, ARRAY_SIZE(hw_lm));
> +
> +
> +	/*
> +	 * There may be 4 PP and 2 INTF for quad pipe case, so INTF is not
> +	 * mapped to PP 1:1. Let's calculate the stride with pipe/INTF
> +	 */
> +	num_pp_per_intf = num_lm / dpu_enc->num_phys_encs;
> +
>  	for (i = 0; i < dpu_enc->num_phys_encs; i++) {
>  		struct dpu_encoder_phys *phys = dpu_enc->phys_encs[i];
>  		struct dpu_hw_ctl *ctl0 = to_dpu_hw_ctl(hw_ctl[0]);
>  
> -		phys->hw_pp = dpu_enc->hw_pp[i];
> +		phys->hw_pp = dpu_enc->hw_pp[num_pp_per_intf * i];
>  		if (!phys->hw_pp) {
>  			DPU_ERROR_ENC(dpu_enc,
>  				"no pp block assigned at idx: %d\n", i);
> 
> -- 
> 2.34.1
>