linux-kernel - Re: [PATCH 08/45] drm/msm/dp: re-arrange dp_display

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Message-ID: <7bscw5btxqonvfo4fqbalhjdhs3hewtkcr3svpxonhsuawzpio@d4wbamnobcdl>
Date: Sun, 8 Dec 2024 14:03:48 +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 08/45] drm/msm/dp: re-arrange dp_display_disable() into
 functional parts

On Thu, Dec 05, 2024 at 08:31:39PM -0800, Abhinav Kumar wrote:
> dp_display_disable() handles special case of when monitor is
> disconnected from the dongle while the dongle stays connected
> thereby needing a separate function dp_ctrl_off_link_stream()
> for this. However with a slight rework this can still be handled
> by keeping common paths same for regular and special case.
> 
> Signed-off-by: Abhinav Kumar <quic_abhinavk@...cinc.com>
> ---
>  drivers/gpu/drm/msm/dp/dp_ctrl.c    | 29 +++++++++++++++--------------
>  drivers/gpu/drm/msm/dp/dp_ctrl.h    |  4 ++++
>  drivers/gpu/drm/msm/dp/dp_display.c | 25 ++++++++++++-------------
>  3 files changed, 31 insertions(+), 27 deletions(-)
> 


Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>

Nevertheless,

> @@ -905,20 +905,19 @@ static int msm_dp_display_disable(struct msm_dp_display_private *dp)
>  	if (!msm_dp_display->power_on)
>  		return 0;
>  
> -	if (dp->link->sink_count == 0) {
> -		/*
> -		 * irq_hpd with sink_count = 0
> -		 * hdmi unplugged out of dongle
> -		 */
> -		msm_dp_ctrl_off_link_stream(dp->ctrl);
> -	} else {
> -		/*
> -		 * unplugged interrupt
> -		 * dongle unplugged out of DUT
> -		 */
> -		msm_dp_ctrl_off(dp->ctrl);
> +	msm_dp_ctrl_clear_vsc_sdp_pkt(dp->ctrl);
> +
> +	/* dongle is still connected but sinks are disconnected */
> +	if (dp->link->sink_count == 0)
> +		msm_dp_ctrl_psm_config(dp->ctrl);
> +
> +	msm_dp_ctrl_off(dp->ctrl);
> +
> +	/* re-init the PHY so that we can listen to Dongle disconnect */
> +	if (dp->link->sink_count == 0)

It might be better to have just two codepaths:

if (sink_count == 0) {
  msm_dp_ctrl_clear_vsc_sdp_pkt()
  msm_dp_ctrl_psm_config()
  msm_dp_ctrl_off()
  msm_dp_ctrl_reinit_phy()
} else {
  msm_dp_ctrl_clear_vsc_sdp_pkt()
  msm_dp_ctrl_off()
  msm_dp_display_host_phy_exit()
}

> +		msm_dp_ctrl_reinit_phy(dp->ctrl);
> +	else
>  		msm_dp_display_host_phy_exit(dp);
> -	}
>  
>  	msm_dp_display->power_on = false;
>  
> 
> -- 
> 2.34.1
> 

-- 
With best wishes
Dmitry