linux-kernel - Re: [PATCH Resend v11 15/15] drm/msm/disp/dpu: update dpu_enc crtc state on crtc enable/disable during self refresh

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Message-ID: <db1e407c-8dd6-733f-e52d-55a1f9e43d6f@linaro.org>
Date:   Tue, 24 Jan 2023 02:30:34 +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:     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, quic_sbillaka@...cinc.com
Subject: Re: [PATCH Resend v11 15/15] drm/msm/disp/dpu: update dpu_enc crtc
 state on crtc enable/disable during self refresh

On 19/01/2023 16:26, Vinod Polimera wrote:
> Populate the enocder software structure to reflect the updated
> crtc appropriately during crtc enable/disable for a new commit
> while taking care of the self refresh transitions when crtc
> disable is triggered from the drm self refresh library.
> 
> Signed-off-by: Vinod Polimera <quic_vpolimer@...cinc.com>
> ---
>   drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c | 31 ++++++++++++++++++++++++++-----
>   1 file changed, 26 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
> index d513aeb4..e8e456a 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
> @@ -1013,14 +1013,23 @@ static void dpu_crtc_disable(struct drm_crtc *crtc,
>   									      crtc);
>   	struct dpu_crtc *dpu_crtc = to_dpu_crtc(crtc);
>   	struct dpu_crtc_state *cstate = to_dpu_crtc_state(crtc->state);
> -	struct drm_encoder *encoder;
> +	struct drm_encoder *encoder = NULL;

Why is this chunk necessary?

>   	unsigned long flags;
>   	bool release_bandwidth = false;
>   
>   	DRM_DEBUG_KMS("crtc%d\n", crtc->base.id);
>   
> -	if (old_crtc_state->self_refresh_active)
> +	/* If disable is triggered while in self refresh mode,
> +	 * reset the encoder software state so that in enable
> +	 * it won't trigger a warn while assigning crtc.
> +	 */
> +	if (old_crtc_state->self_refresh_active) {
> +		drm_for_each_encoder_mask(encoder, crtc->dev,
> +					old_crtc_state->encoder_mask) {
> +			dpu_encoder_assign_crtc(encoder, NULL);
> +		}
>   		return;
> +	}
>   
>   	/* Disable/save vblank irq handling */
>   	drm_crtc_vblank_off(crtc);
> @@ -1033,7 +1042,14 @@ static void dpu_crtc_disable(struct drm_crtc *crtc,
>   		 */
>   		if (dpu_encoder_get_intf_mode(encoder) == INTF_MODE_VIDEO)
>   			release_bandwidth = true;
> -		dpu_encoder_assign_crtc(encoder, NULL);
> +
> +		/*
> +		 * If disable is triggered during psr active(e.g: screen dim in PSR),
> +		 * we will need encoder->crtc connection to process the device sleep &
> +		 * preserve it during psr sequence.
> +		 */
> +		if (!crtc->state->self_refresh_active)
> +			dpu_encoder_assign_crtc(encoder, NULL);
>   	}
>   
>   	/* wait for frame_event_done completion */
> @@ -1081,6 +1097,9 @@ static void dpu_crtc_enable(struct drm_crtc *crtc,
>   	struct dpu_crtc *dpu_crtc = to_dpu_crtc(crtc);
>   	struct drm_encoder *encoder;
>   	bool request_bandwidth = false;
> +	struct drm_crtc_state *old_crtc_state;
> +
> +	old_crtc_state = drm_atomic_get_old_crtc_state(state, crtc);
>   
>   	pm_runtime_get_sync(crtc->dev->dev);
>   
> @@ -1103,8 +1122,10 @@ static void dpu_crtc_enable(struct drm_crtc *crtc,
>   	trace_dpu_crtc_enable(DRMID(crtc), true, dpu_crtc);
>   	dpu_crtc->enabled = true;
>   
> -	drm_for_each_encoder_mask(encoder, crtc->dev, crtc->state->encoder_mask)
> -		dpu_encoder_assign_crtc(encoder, crtc);
> +	if (!old_crtc_state->self_refresh_active) {
> +		drm_for_each_encoder_mask(encoder, crtc->dev, crtc->state->encoder_mask)
> +			dpu_encoder_assign_crtc(encoder, crtc);
> +	}
>   
>   	/* Enable/restore vblank irq handling */
>   	drm_crtc_vblank_on(crtc);

-- 
With best wishes
Dmitry