Message-ID: <01f61ae7-dfa0-6c21-d1ac-3ae428c3f5e2@linaro.org>
Date:   Mon, 30 Jan 2023 21:17:32 +0200
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Subject: Re: [v1 3/3] drm/msm/disp/dpu1: reserve the resources on topology
 change
To:     Kalyan Thota <quic_kalyant@quicinc.com>,
        dri-devel@lists.freedesktop.org, linux-arm-msm@vger.kernel.org,
        freedreno@lists.freedesktop.org, devicetree@vger.kernel.org
Cc:     linux-kernel@vger.kernel.org, robdclark@chromium.org,
        dianders@chromium.org, swboyd@chromium.org,
        quic_vpolimer@quicinc.com, quic_abhinavk@quicinc.com,
        marijn.suijten@somainline.org
References: <1675092092-26412-1-git-send-email-quic_kalyant@quicinc.com>
 <1675092092-26412-4-git-send-email-quic_kalyant@quicinc.com>
Content-Language: en-GB
From:   Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
In-Reply-To: <1675092092-26412-4-git-send-email-quic_kalyant@quicinc.com>
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Precedence: bulk

On 30/01/2023 17:21, Kalyan Thota wrote:
> Some features like ctm can be enabled dynamically. Release and reserve
> the dpu resources whenever a topology change occurs such that
> required hw blocks are allocated appropriately.
> 
> Changes in v1:
> - Avoid mode_set call directly instead change the mode_changed (Dmitry)

Thanks, I like the overall idea. Minor nits below.

Also, could you please fix your scripts to include the PATCH keyword 
into the subject? If you do `git format-patches -# -v#`, where # is the 
number of commits to include and the version of the patchset, it will do 
the trick on its own.

> 
> Signed-off-by: Kalyan Thota <quic_kalyant@quicinc.com>
> ---
>   drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.h    |  2 ++
>   drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c | 42 ++++++++++++++++++-----------
>   drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h |  4 ++-
>   3 files changed, 32 insertions(+), 16 deletions(-)
> 
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.h b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.h
> index 539b68b..58e8c72 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.h
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.h
> @@ -204,6 +204,7 @@ struct dpu_crtc {
>    * @hw_ctls       : List of active ctl paths
>    * @crc_source    : CRC source
>    * @crc_frame_skip_count: Number of frames skipped before getting CRC
> + * @ctm_enabled   : Cached ctm reservation state

Nit: we do not reserve CTMs. We reserve DSPPs.
So, ctm_enabled is 'Cached color management enablement state'.

>    */
>   struct dpu_crtc_state {
>   	struct drm_crtc_state base;
> @@ -225,6 +226,7 @@ struct dpu_crtc_state {
>   
>   	enum dpu_crtc_crc_source crc_source;
>   	int crc_frame_skip_count;
> +	bool ctm_enabled;
>   };
>   
>   #define to_dpu_crtc_state(x) \
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> index 3bd46b4..0ddf2c9 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> @@ -217,6 +217,22 @@ static u32 dither_matrix[DITHER_MATRIX_SZ] = {
>   	15, 7, 13, 5, 3, 11, 1, 9, 12, 4, 14, 6, 0, 8, 2, 10
>   };
>   
> +static bool _dpu_enc_is_dspps_changed(struct drm_crtc_state *crtc_state,
> +	struct msm_display_topology topology)
> +{
> +	struct dpu_crtc_state *cstate = to_dpu_crtc_state(crtc_state);
> +
> +	if (drm_atomic_crtc_needs_modeset(crtc_state))
> +		return true;
> +
> +	if ((cstate->ctm_enabled && !topology.num_dspp) ||
> +	    (!cstate->ctm_enabled && topology.num_dspp)) {
> +		crtc_state->mode_changed = true;
> +		return true;
> +	}
> +
> +	return false;
> +}
>   
>   bool dpu_encoder_is_widebus_enabled(const struct drm_encoder *drm_enc)
>   {
> @@ -638,25 +654,21 @@ static int dpu_encoder_virt_atomic_check(
>   		if (ret) {
>   			DPU_ERROR_ENC(dpu_enc,
>   					"mode unsupported, phys idx %d\n", i);
> -			break;
> +			return ret;

This deserves a separate commit with the proper Fixes: tag.

>   		}
>   	}
>   
>   	topology = dpu_encoder_get_topology(dpu_enc, dpu_kms, adj_mode, crtc_state);
>   
> +	_dpu_enc_is_dspps_changed(crtc_state, topology);
> +
>   	/* Reserve dynamic resources now. */
> -	if (!ret) {
> -		/*
> -		 * Release and Allocate resources on every modeset
> -		 * Dont allocate when active is false.
> -		 */
> -		if (drm_atomic_crtc_needs_modeset(crtc_state)) {
> -			dpu_rm_release(global_state, drm_enc);
> +	if (drm_atomic_crtc_needs_modeset(crtc_state)) {
> +		dpu_rm_release(global_state, drm_enc);
>   
> -			if (!crtc_state->active_changed || crtc_state->active)
> -				ret = dpu_rm_reserve(&dpu_kms->rm, global_state,
> -						drm_enc, crtc_state, topology);
> -		}
> +		if (crtc_state->enable)
> +			ret = dpu_rm_reserve(&dpu_kms->rm, global_state,
> +					drm_enc, crtc_state, topology);
>   	}
>   
>   	trace_dpu_enc_atomic_check_flags(DRMID(drm_enc), adj_mode->flags);
> @@ -1027,7 +1039,7 @@ static void dpu_encoder_virt_atomic_mode_set(struct drm_encoder *drm_enc,
>   	struct dpu_hw_blk *hw_lm[MAX_CHANNELS_PER_ENC];
>   	struct dpu_hw_blk *hw_dspp[MAX_CHANNELS_PER_ENC] = { NULL };
>   	struct dpu_hw_blk *hw_dsc[MAX_CHANNELS_PER_ENC];
> -	int num_lm, num_ctl, num_pp, num_dsc;
> +	int num_lm, num_ctl, num_pp, num_dsc, num_dspp;
>   	unsigned int dsc_mask = 0;
>   	int i;
>   
> @@ -1058,7 +1070,7 @@ static void dpu_encoder_virt_atomic_mode_set(struct drm_encoder *drm_enc,
>   		drm_enc->base.id, DPU_HW_BLK_CTL, hw_ctl, ARRAY_SIZE(hw_ctl));
>   	num_lm = dpu_rm_get_assigned_resources(&dpu_kms->rm, global_state,
>   		drm_enc->base.id, DPU_HW_BLK_LM, hw_lm, ARRAY_SIZE(hw_lm));
> -	dpu_rm_get_assigned_resources(&dpu_kms->rm, global_state,
> +	num_dspp = dpu_rm_get_assigned_resources(&dpu_kms->rm, global_state,
>   		drm_enc->base.id, DPU_HW_BLK_DSPP, hw_dspp,
>   		ARRAY_SIZE(hw_dspp));
>   
> @@ -1089,7 +1101,7 @@ static void dpu_encoder_virt_atomic_mode_set(struct drm_encoder *drm_enc,
>   	}
>   
>   	cstate->num_mixers = num_lm;
> -
> +	cstate->ctm_enabled = !!num_dspp;
>   	dpu_enc->connector = conn_state->connector;
>   
>   	for (i = 0; i < dpu_enc->num_phys_encs; i++) {
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h
> index 9e7236e..4cbe20c 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h
> @@ -150,8 +150,10 @@ int dpu_encoder_setup(struct drm_device *dev, struct drm_encoder *enc,
>    * dpu_encoder_prepare_commit - prepare encoder at the very beginning of an
>    *	atomic commit, before any registers are written
>    * @drm_enc:    Pointer to previously created drm encoder structure
> + * @crtc_state: Pointer to drm crtc state
>    */
> -void dpu_encoder_prepare_commit(struct drm_encoder *drm_enc);
> +void dpu_encoder_prepare_commit(struct drm_encoder *drm_enc,
> +		struct drm_crtc_state *crtc_state);

I think this change on it's own breaks compilation. Please drop it.

>   
>   /**
>    * dpu_encoder_set_idle_timeout - set the idle timeout for video

-- 
With best wishes
Dmitry