linux-kernel - Re: [PATCH 23/45] drm/msm/dp: always program MST_FIFO_CONSTANT

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Message-ID: <lks6otgplrjldckvce6a3jrofefm7q3kp5swab6y5hk22iz6f3@lp2pg7kzzhoq>
Date: Sun, 8 Dec 2024 13:44:27 +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 23/45] drm/msm/dp: always program MST_FIFO_CONSTANT_FILL
 for MST

On Thu, Dec 05, 2024 at 08:31:54PM -0800, Abhinav Kumar wrote:
> As required by the hardware programming guide, always program
> the MST_FIFO_CONSTANT_FILL for MST use-cases.
> 
> Signed-off-by: Abhinav Kumar <quic_abhinavk@...cinc.com>
> ---
>  drivers/gpu/drm/msm/dp/dp_catalog.c | 24 ++++++++++++++++++++++++
>  drivers/gpu/drm/msm/dp/dp_catalog.h |  1 +
>  drivers/gpu/drm/msm/dp/dp_ctrl.c    |  3 +++
>  3 files changed, 28 insertions(+)
> 
> diff --git a/drivers/gpu/drm/msm/dp/dp_catalog.c b/drivers/gpu/drm/msm/dp/dp_catalog.c
> index 4826a698979ce7c37112812299879411c5743fa9..3cfa9fd0c6f5e664a65e6d9b74e5c9f22ad711f2 100644
> --- a/drivers/gpu/drm/msm/dp/dp_catalog.c
> +++ b/drivers/gpu/drm/msm/dp/dp_catalog.c
> @@ -1009,6 +1009,30 @@ int msm_dp_catalog_panel_timing_cfg(struct msm_dp_catalog *msm_dp_catalog, u32 t
>  	return 0;
>  }
>  
> +int msm_dp_catalog_mst_async_fifo(struct msm_dp_catalog *msm_dp_catalog)
> +{
> +	struct msm_dp_catalog_private *catalog = container_of(msm_dp_catalog,
> +							      struct msm_dp_catalog_private,
> +							      msm_dp_catalog);
> +
> +	u32 reg;
> +
> +	if (msm_dp_catalog->stream_id == DP_STREAM_0)
> +		reg = msm_dp_read_p0(catalog, MMSS_DP_ASYNC_FIFO_CONFIG);
> +	else
> +		reg = msm_dp_read_p1(catalog, MMSS_DP_ASYNC_FIFO_CONFIG);
> +
> +	/* enable MST_FIFO_CONSTANT_FILL */
> +	reg |= BIT(0);

#define

> +
> +	if (msm_dp_catalog->stream_id == DP_STREAM_0)
> +		msm_dp_write_p0(catalog, MMSS_DP_ASYNC_FIFO_CONFIG, reg);
> +	else
> +		msm_dp_write_p1(catalog, MMSS_DP_ASYNC_FIFO_CONFIG, reg);
> +
> +	return 0;
> +}
> +
>  static void msm_dp_catalog_panel_send_vsc_sdp(struct msm_dp_catalog *msm_dp_catalog, struct dp_sdp *vsc_sdp)
>  {
>  	struct msm_dp_catalog_private *catalog;
> diff --git a/drivers/gpu/drm/msm/dp/dp_catalog.h b/drivers/gpu/drm/msm/dp/dp_catalog.h
> index 323858c587f85996d296156c7b8b201cdb7b7eb4..0025ecc0adb2f351c44f10af82332a6622749416 100644
> --- a/drivers/gpu/drm/msm/dp/dp_catalog.h
> +++ b/drivers/gpu/drm/msm/dp/dp_catalog.h
> @@ -150,5 +150,6 @@ void msm_dp_catalog_mst_channel_alloc(struct msm_dp_catalog *ctrl,
>  				      u32 ch, u32 ch_start_slot, u32 tot_slot_cnt);
>  void msm_dp_catalog_ctrl_update_rg(struct msm_dp_catalog *ctrl, u32 stream,
>  				   u32 x_int, u32 y_frac_enum);
> +int msm_dp_catalog_mst_async_fifo(struct msm_dp_catalog *dp_catalog);
>  
>  #endif /* _DP_CATALOG_H_ */
> diff --git a/drivers/gpu/drm/msm/dp/dp_ctrl.c b/drivers/gpu/drm/msm/dp/dp_ctrl.c
> index 2288c379283c721a01c81302f8d307d0b3c76527..d4915a962f97b3d2a347456e197265a5dc043eb0 100644
> --- a/drivers/gpu/drm/msm/dp/dp_ctrl.c
> +++ b/drivers/gpu/drm/msm/dp/dp_ctrl.c
> @@ -236,6 +236,9 @@ static void msm_dp_ctrl_configure_source_params(struct msm_dp_ctrl_private *ctrl
>  	cc = msm_dp_link_get_colorimetry_config(ctrl->link);
>  	msm_dp_catalog_ctrl_config_misc(ctrl->catalog, cc, tb);
>  	msm_dp_panel_timing_cfg(msm_dp_panel);
> +
> +	if (ctrl->mst_active)
> +		msm_dp_catalog_mst_async_fifo(ctrl->catalog);

Should it be disabled further on in a non-MST case?

>  }
>  
>  /*
> 
> -- 
> 2.34.1
> 

-- 
With best wishes
Dmitry