linux-kernel - Re: [PATCH 43/45] drm/msm/dp: populate the max

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Message-ID: <5hmhxnqp3ix636jdsxqgmdkrzvsduax4ft5uec35qduuwif2rz@pwbm6hchctrw>
Date: Sun, 8 Dec 2024 14:00:34 +0200
From: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To: Abhinav Kumar <quic_abhinavk@...cinc.com>
Cc: Rob Clark <robdclark@...il.com>, Sean Paul <sean@...rly.run>, 
	Marijn Suijten <marijn.suijten@...ainline.org>, David Airlie <airlied@...il.com>, 
	Simona Vetter <simona@...ll.ch>, Stephen Boyd <swboyd@...omium.org>, 
	Chandan Uddaraju <chandanu@...eaurora.org>, Guenter Roeck <groeck@...omium.org>, 
	Kuogee Hsieh <quic_khsieh@...cinc.com>, Bjorn Andersson <andersson@...nel.org>, 
	Konrad Dybcio <konradybcio@...nel.org>, Rob Herring <robh@...nel.org>, 
	Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley <conor+dt@...nel.org>, 
	Vara Reddy <quic_varar@...cinc.com>, Rob Clark <robdclark@...omium.org>, 
	Tanmay Shah <tanmay@...eaurora.org>, linux-arm-msm@...r.kernel.org, dri-devel@...ts.freedesktop.org, 
	freedreno@...ts.freedesktop.org, linux-kernel@...r.kernel.org, devicetree@...r.kernel.org, 
	Jessica Zhang <quic_jesszhan@...cinc.com>, Laurent Pinchart <laurent.pinchart@...asonboard.com>
Subject: Re: [PATCH 43/45] drm/msm/dp: populate the max_streams for sa8775
 mst controller

On Thu, Dec 05, 2024 at 08:32:14PM -0800, Abhinav Kumar wrote:
> Populate the max_streams for DP controllers to indicate MST support.
> 
> If the pixel clock handle for the second stream fails, treat it as
> SST case rather than a complete failure.

Could you possibly clarify:
- Are there MSM DP controllers which do not support MST?
- Are there MSM DP controller which support more than 2 streams?

It might be easier to to set max_streams statically rather than setting
it via the descs.

> 
> Signed-off-by: Abhinav Kumar <quic_abhinavk@...cinc.com>
> ---
>  drivers/gpu/drm/msm/dp/dp_ctrl.c    |  9 +++++++++
>  drivers/gpu/drm/msm/dp/dp_ctrl.h    |  2 ++
>  drivers/gpu/drm/msm/dp/dp_display.c | 13 ++++++++++---
>  3 files changed, 21 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/msm/dp/dp_ctrl.c b/drivers/gpu/drm/msm/dp/dp_ctrl.c
> index d4915a962f97b3d2a347456e197265a5dc043eb0..0e5ebcdab00936cf0ce6e35514f2932158530cc0 100644
> --- a/drivers/gpu/drm/msm/dp/dp_ctrl.c
> +++ b/drivers/gpu/drm/msm/dp/dp_ctrl.c
> @@ -2438,6 +2438,15 @@ static int msm_dp_ctrl_clk_init(struct msm_dp_ctrl *msm_dp_ctrl)
>  	return 0;
>  }
>  
> +int msm_dp_ctrl_get_stream_cnt(struct msm_dp_ctrl *msm_dp_ctrl)
> +{
> +	struct msm_dp_ctrl_private *ctrl;
> +
> +	ctrl = container_of(msm_dp_ctrl, struct msm_dp_ctrl_private, msm_dp_ctrl);
> +
> +	return ctrl->num_pixel_clks;
> +}
> +
>  struct msm_dp_ctrl *msm_dp_ctrl_get(struct device *dev, struct msm_dp_link *link,
>  			struct msm_dp_panel *panel,	struct drm_dp_aux *aux,
>  			struct msm_dp_catalog *catalog,
> diff --git a/drivers/gpu/drm/msm/dp/dp_ctrl.h b/drivers/gpu/drm/msm/dp/dp_ctrl.h
> index 9ad7022d6217572395d69294c3cc4d4dbaddf0ac..f72a499809ec01a9cc5bb79762bc2604820426a1 100644
> --- a/drivers/gpu/drm/msm/dp/dp_ctrl.h
> +++ b/drivers/gpu/drm/msm/dp/dp_ctrl.h
> @@ -54,4 +54,6 @@ void msm_dp_ctrl_set_mst_channel_info(struct msm_dp_ctrl *msm_dp_ctrl,
>  				      u32 start_slot, u32 tot_slots);
>  void msm_dp_ctrl_push_vcpf(struct msm_dp_ctrl *dp_ctrl, struct msm_dp_panel *msm_dp_panel);
>  
> +int msm_dp_ctrl_get_stream_cnt(struct msm_dp_ctrl *dp_ctrl);
> +
>  #endif /* _DP_CTRL_H_ */
> diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
> index 528cda1453a85f5f8dd37bb0d2366548016c88e4..db563af19461089dbcaccce0d03fd03d5aa567aa 100644
> --- a/drivers/gpu/drm/msm/dp/dp_display.c
> +++ b/drivers/gpu/drm/msm/dp/dp_display.c
> @@ -126,6 +126,7 @@ struct msm_dp_desc {
>  	unsigned int id;
>  	bool wide_bus_supported;
>  	const unsigned int *intf_map;
> +	unsigned int max_streams;
>  };
>  
>  /* to be kept in sync with enum dpu_intf of dpu_hw_mdss.h */
> @@ -149,10 +150,10 @@ static const unsigned int stream_intf_map_sa_8775p[][DP_STREAM_MAX] = {
>  };
>  
>  static const struct msm_dp_desc msm_dp_desc_sa8775p[] = {
> -	{ .io_start = 0x0af54000, .id = MSM_DP_CONTROLLER_0, .wide_bus_supported = true,
> +	{ .io_start = 0x0af54000, .id = MSM_DP_CONTROLLER_0, .wide_bus_supported = true, .max_streams = 2,
>  	  .intf_map = stream_intf_map_sa_8775p[MSM_DP_CONTROLLER_0],
>  	},
> -	{ .io_start = 0x0af5c000, .id = MSM_DP_CONTROLLER_1, .wide_bus_supported = true,
> +	{ .io_start = 0x0af5c000, .id = MSM_DP_CONTROLLER_1, .wide_bus_supported = true, .max_streams = 2,
>  	  .intf_map = stream_intf_map_sa_8775p[MSM_DP_CONTROLLER_1],
>  	},
>  	{ .io_start = 0x22154000, .id = MSM_DP_CONTROLLER_2, .wide_bus_supported = true },
> @@ -1481,7 +1482,10 @@ int msm_dp_get_mst_max_stream(const struct msm_dp *dp_display)
>  
>  	dp_priv = container_of(dp_display, struct msm_dp_display_private, msm_dp_display);
>  
> -	return dp_priv->max_stream;
> +	if (dp_priv->max_stream == msm_dp_ctrl_get_stream_cnt(dp_priv->ctrl))
> +		return dp_priv->max_stream;
> +	else
> +		return DEFAULT_STREAM_COUNT;
>  }
>  
>  int msm_dp_mst_bridge_init(struct msm_dp *dp_display, struct drm_encoder *encoder)
> @@ -1517,6 +1521,9 @@ static int msm_dp_display_probe(struct platform_device *pdev)
>  
>  	dp->max_stream = DEFAULT_STREAM_COUNT;
>  
> +	if (desc->max_streams > DEFAULT_STREAM_COUNT)
> +		dp->max_stream = desc->max_streams;
> +
>  	dp->intf_map = desc->intf_map;
>  
>  	rc = msm_dp_init_sub_modules(dp);
> 
> -- 
> 2.34.1
> 

-- 
With best wishes
Dmitry