Re: [PATCH] drm/i915/psr: Request modeset on initial commit to compute PSR state

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Tue, Jan 23, 2024 at 09:11:03AM +0200, Jouni Högander wrote:
> We want to request full modeset in initial fast check to force PSR state
> computation. Otherwise PSR is not enabled on initial commit but on first
> commit with modeset or fastset. With this change Initial commit will still
> end up using fastset (unless something else requires full modeset) as PSR
> parameters are not anymore part of intel_pipe_config_compare.

I think I'd prefer to go the oppostie direction and try to get all
the full modeset stuff out from the initial commit. The only reason
the initial commit was introduced was to compute the plane states
due to lack of readout, and then it got extended due to various other
hacks. Our goal is to inherit the state from the BIOS so ideally
the whole initial_commit thing wouldn't even exist.

> 
> Cc: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
> 
> Fixes: a480dd59fe25 ("drm/i915/display: No need for full modeset due to psr")
> Signed-off-by: Jouni Högander <jouni.hogander@intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_dp.c  | 8 ++++++++
>  drivers/gpu/drm/i915/display/intel_psr.c | 3 ---
>  drivers/gpu/drm/i915/display/intel_psr.h | 3 +++
>  3 files changed, 11 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
> index ab415f41924d..143981b91e8b 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -3326,6 +3326,14 @@ bool intel_dp_initial_fastset_check(struct intel_encoder *encoder,
>  		fastset = false;
>  	}
>  
> +	if (CAN_PSR(intel_dp)) {
> +		drm_dbg_kms(&i915->drm, "[ENCODER:%d:%s] Forcing full modeset to compute PSR state\
> +n",
> +			    encoder->base.base.id, encoder->base.name);
> +		crtc_state->uapi.mode_changed = true;
> +		fastset = false;
> +	}
> +
>  	return fastset;
>  }
>  
> diff --git a/drivers/gpu/drm/i915/display/intel_psr.c b/drivers/gpu/drm/i915/display/intel_psr.c
> index 1010b8c405df..b6db7dbfaf1a 100644
> --- a/drivers/gpu/drm/i915/display/intel_psr.c
> +++ b/drivers/gpu/drm/i915/display/intel_psr.c
> @@ -173,9 +173,6 @@
>   * irrelevant for normal operation.
>   */
>  
> -#define CAN_PSR(intel_dp) ((intel_dp)->psr.sink_support && \
> -			   (intel_dp)->psr.source_support)
> -
>  #define CAN_PANEL_REPLAY(intel_dp) ((intel_dp)->psr.sink_panel_replay_support && \
>  				    (intel_dp)->psr.source_panel_replay_support)
>  
> diff --git a/drivers/gpu/drm/i915/display/intel_psr.h b/drivers/gpu/drm/i915/display/intel_psr.h
> index cde781df84d5..3d9920ebafab 100644
> --- a/drivers/gpu/drm/i915/display/intel_psr.h
> +++ b/drivers/gpu/drm/i915/display/intel_psr.h
> @@ -21,6 +21,9 @@ struct intel_encoder;
>  struct intel_plane;
>  struct intel_plane_state;
>  
> +#define CAN_PSR(intel_dp) ((intel_dp)->psr.sink_support && \
> +			   (intel_dp)->psr.source_support)
> +
>  bool intel_encoder_can_psr(struct intel_encoder *encoder);
>  void intel_psr_init_dpcd(struct intel_dp *intel_dp);
>  void intel_psr_pre_plane_update(struct intel_atomic_state *state,
> -- 
> 2.34.1

-- 
Ville Syrjälä
Intel