linux-kernel - Re: [PATCH Resend v11 05/15] drm/msm/dp: disable self_refresh

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Message-ID: <4a359748-e53c-a178-de09-2c999eb69013@linaro.org>
Date:   Tue, 24 Jan 2023 02:21:31 +0200
From:   Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To:     Vinod Polimera <quic_vpolimer@...cinc.com>,
        dri-devel@...ts.freedesktop.org, linux-arm-msm@...r.kernel.org,
        freedreno@...ts.freedesktop.org, devicetree@...r.kernel.org
Cc:     Sankeerth Billakanti <quic_sbillaka@...cinc.com>,
        linux-kernel@...r.kernel.org, robdclark@...il.com,
        dianders@...omium.org, swboyd@...omium.org,
        quic_kalyant@...cinc.com, quic_khsieh@...cinc.com,
        quic_vproddut@...cinc.com, quic_bjorande@...cinc.com,
        quic_abhinavk@...cinc.com
Subject: Re: [PATCH Resend v11 05/15] drm/msm/dp: disable self_refresh_aware
 after entering psr

On 19/01/2023 16:26, Vinod Polimera wrote:
> From: Sankeerth Billakanti <quic_sbillaka@...cinc.com>
> 
> Updated frames get queued if self_refresh_aware is set when the
> sink is in psr. To support bridge enable and avoid queuing of update
> frames, reset the self_refresh_aware state after entering psr.

I'm not convinced by this change. E.g. analogix code doesn't do this. 
Could you please clarify, why do you need to toggle the 
self_refresh_aware flag?

> 
> Signed-off-by: Sankeerth Billakanti <quic_sbillaka@...cinc.com>
> Signed-off-by: Vinod Polimera <quic_vpolimer@...cinc.com>
> ---
>   drivers/gpu/drm/msm/dp/dp_drm.c | 27 ++++++++++++++++++++++++++-
>   1 file changed, 26 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/msm/dp/dp_drm.c b/drivers/gpu/drm/msm/dp/dp_drm.c
> index 029e08c..92d1a1b 100644
> --- a/drivers/gpu/drm/msm/dp/dp_drm.c
> +++ b/drivers/gpu/drm/msm/dp/dp_drm.c
> @@ -134,6 +134,8 @@ static void edp_bridge_atomic_enable(struct drm_bridge *drm_bridge,
>   	struct drm_crtc_state *old_crtc_state;
>   	struct msm_dp_bridge *dp_bridge = to_dp_bridge(drm_bridge);
>   	struct msm_dp *dp = dp_bridge->dp_display;
> +	struct drm_connector *connector;
> +	struct drm_connector_state *conn_state = NULL;
>   
>   	/*
>   	 * Check the old state of the crtc to determine if the panel
> @@ -150,10 +152,22 @@ static void edp_bridge_atomic_enable(struct drm_bridge *drm_bridge,
>   
>   	if (old_crtc_state && old_crtc_state->self_refresh_active) {
>   		dp_display_set_psr(dp, false);
> -		return;
> +		goto psr_aware;
>   	}
>   
>   	dp_bridge_atomic_enable(drm_bridge, old_bridge_state);
> +
> +psr_aware:
> +	connector = drm_atomic_get_new_connector_for_encoder(atomic_state,
> +							drm_bridge->encoder);
> +	if (connector)
> +		conn_state = drm_atomic_get_new_connector_state(atomic_state,
> +								connector);
> +
> +	if (conn_state) {
> +		conn_state->self_refresh_aware = dp->psr_supported;
> +	}

No need to wrap a single line statement in brackets.

> +
>   }
>   
>   static void edp_bridge_atomic_disable(struct drm_bridge *drm_bridge,
> @@ -164,6 +178,14 @@ static void edp_bridge_atomic_disable(struct drm_bridge *drm_bridge,
>   	struct drm_crtc_state *new_crtc_state = NULL, *old_crtc_state = NULL;
>   	struct msm_dp_bridge *dp_bridge = to_dp_bridge(drm_bridge);
>   	struct msm_dp *dp = dp_bridge->dp_display;
> +	struct drm_connector *connector;
> +	struct drm_connector_state *conn_state = NULL;
> +
> +	connector = drm_atomic_get_old_connector_for_encoder(atomic_state,
> +							drm_bridge->encoder);
> +	if (connector)
> +		conn_state = drm_atomic_get_new_connector_state(atomic_state,
> +								connector);
>   
>   	crtc = drm_atomic_get_old_crtc_for_encoder(atomic_state,
>   						   drm_bridge->encoder);
> @@ -190,6 +212,9 @@ static void edp_bridge_atomic_disable(struct drm_bridge *drm_bridge,
>   	 * when display disable occurs while the sink is in psr state.
>   	 */
>   	if (new_crtc_state->self_refresh_active) {
> +		if (conn_state)
> +			conn_state->self_refresh_aware = false;
> +
>   		dp_display_set_psr(dp, true);
>   		return;
>   	} else if (old_crtc_state->self_refresh_active) {

-- 
With best wishes
Dmitry