Re: [PATCH v2 4/4] drm/msm/dpu: reserve the resources on topology change

[Dmitry Baryshkov]

On 07/02/2023 16:29, 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.
>
> Signed-off-by: Kalyan Thota <quic_kalyant@xxxxxxxxxxx>
> ---
> Changes in v1:
> - Avoid mode_set call directly (Dmitry)
>
> Changes in v2:
> - Minor nits (Dmitry)
> ---
>   drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.h    |  2 ++
>   drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c | 27 ++++++++++++++++++++++-----
>   2 files changed, 24 insertions(+), 5 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..85bd5645 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 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 3920efd..7bb4840 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_dspp_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;

I think this check doesn't belong to the is_dspp_changed() function.

> +
> +	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)
>   {
> @@ -642,14 +658,15 @@ static int dpu_encoder_virt_atomic_check(
>   
>   	topology = dpu_encoder_get_topology(dpu_enc, dpu_kms, adj_mode, crtc_state);
>   
> +	_dpu_enc_is_dspp_changed(crtc_state, topology);
> +
>   	/*
>   	 * 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 (!crtc_state->active_changed || crtc_state->active)
> +		if (crtc_state->enable)
>   			ret = dpu_rm_reserve(&dpu_kms->rm, global_state,
>   					drm_enc, crtc_state, topology);
>   	}
> @@ -1022,7 +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;
>   
> @@ -1053,7 +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));
>   
> @@ -1084,7 +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++) {

--
With best wishes
Dmitry