[PATCH 6/6] drm/i915: Extract ilk_must_disable_lp_wm()

[Murthy, Arun R]

> -----Original Message-----
> From: Intel-gfx <intel-gfx-bounces at lists.freedesktop.org> On Behalf Of Ville
> Syrjala
> Sent: Wednesday, March 20, 2024 9:34 PM
> To: intel-gfx at lists.freedesktop.org
> Subject: [PATCH 6/6] drm/i915: Extract ilk_must_disable_lp_wm()
> 
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> 
> Pull the ilk/snb/ivb LP watermark disable checks into a separate function similar
> to the gmch counterpart (i9xx_must_disable_cxsr()).
> Reduces the clutter in intel_plane_atomic_calc_changes() significantly.
> 
Looks good to me.
Can this patch be taken out of this series as it has no close relation with async.
With taking this patch separately
Reviewed-by: Arun R Murthy <arun.r.murthy at intel.com>

Thanks and Regards,
Arun R Murthy
-------------------

> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> ---
>  .../gpu/drm/i915/display/intel_atomic_plane.c | 95 +++++++++++--------
>  1 file changed, 57 insertions(+), 38 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_atomic_plane.c
> b/drivers/gpu/drm/i915/display/intel_atomic_plane.c
> index b083b985d170..19bcf5754ee2 100644
> --- a/drivers/gpu/drm/i915/display/intel_atomic_plane.c
> +++ b/drivers/gpu/drm/i915/display/intel_atomic_plane.c
> @@ -482,6 +482,61 @@ static bool i9xx_must_disable_cxsr(const struct
> intel_crtc_state *new_crtc_state
>  	return old_ctl != new_ctl;
>  }
> 
> +static bool ilk_must_disable_lp_wm(const struct intel_crtc_state
> *new_crtc_state,
> +				   const struct intel_plane_state
> *old_plane_state,
> +				   const struct intel_plane_state
> *new_plane_state) {
> +	struct intel_plane *plane = to_intel_plane(new_plane_state-
> >uapi.plane);
> +	bool old_visible = old_plane_state->uapi.visible;
> +	bool new_visible = new_plane_state->uapi.visible;
> +	bool modeset, turn_on;
> +
> +	if (plane->id == PLANE_CURSOR)
> +		return false;
> +
> +	modeset = intel_crtc_needs_modeset(new_crtc_state);
> +	turn_on = new_visible && (!old_visible || modeset);
> +
> +	/*
> +	 * ILK/SNB DVSACNTR/Sprite Enable
> +	 * IVB SPR_CTL/Sprite Enable
> +	 * "When in Self Refresh Big FIFO mode, a write to enable the
> +	 *  plane will be internally buffered and delayed while Big FIFO
> +	 *  mode is exiting."
> +	 *
> +	 * Which means that enabling the sprite can take an extra frame
> +	 * when we start in big FIFO mode (LP1+). Thus we need to drop
> +	 * down to LP0 and wait for vblank in order to make sure the
> +	 * sprite gets enabled on the next vblank after the register write.
> +	 * Doing otherwise would risk enabling the sprite one frame after
> +	 * we've already signalled flip completion. We can resume LP1+
> +	 * once the sprite has been enabled.
> +	 *
> +	 * With experimental results seems this is needed also for primary
> +	 * plane, not only sprite plane.
> +	 */
> +	if (turn_on)
> +		return true;
> +
> +	/*
> +	 * WaCxSRDisabledForSpriteScaling:ivb
> +	 * IVB SPR_SCALE/Scaling Enable
> +	 * "Low Power watermarks must be disabled for at least one
> +	 *  frame before enabling sprite scaling, and kept disabled
> +	 *  until sprite scaling is disabled."
> +	 *
> +	 * ILK/SNB DVSASCALE/Scaling Enable
> +	 * "When in Self Refresh Big FIFO mode, scaling enable will be
> +	 *  masked off while Big FIFO mode is exiting."
> +	 *
> +	 * Despite the w/a only being listed for IVB we assume that
> +	 * the ILK/SNB note has similar ramifications, hence we apply
> +	 * the w/a on all three platforms.
> +	 */
> +	return !intel_plane_is_scaled(old_plane_state) &&
> +		intel_plane_is_scaled(new_plane_state);
> +}
> +
>  static int intel_plane_atomic_calc_changes(const struct intel_crtc_state
> *old_crtc_state,
>  					   struct intel_crtc_state
> *new_crtc_state,
>  					   const struct intel_plane_state
> *old_plane_state, @@ -557,44 +612,8 @@ static int
> intel_plane_atomic_calc_changes(const struct intel_crtc_state *old_cr
>  	    i9xx_must_disable_cxsr(new_crtc_state, old_plane_state,
> new_plane_state))
>  		new_crtc_state->disable_cxsr = true;
> 
> -	/*
> -	 * ILK/SNB DVSACNTR/Sprite Enable
> -	 * IVB SPR_CTL/Sprite Enable
> -	 * "When in Self Refresh Big FIFO mode, a write to enable the
> -	 *  plane will be internally buffered and delayed while Big FIFO
> -	 *  mode is exiting."
> -	 *
> -	 * Which means that enabling the sprite can take an extra frame
> -	 * when we start in big FIFO mode (LP1+). Thus we need to drop
> -	 * down to LP0 and wait for vblank in order to make sure the
> -	 * sprite gets enabled on the next vblank after the register write.
> -	 * Doing otherwise would risk enabling the sprite one frame after
> -	 * we've already signalled flip completion. We can resume LP1+
> -	 * once the sprite has been enabled.
> -	 *
> -	 *
> -	 * WaCxSRDisabledForSpriteScaling:ivb
> -	 * IVB SPR_SCALE/Scaling Enable
> -	 * "Low Power watermarks must be disabled for at least one
> -	 *  frame before enabling sprite scaling, and kept disabled
> -	 *  until sprite scaling is disabled."
> -	 *
> -	 * ILK/SNB DVSASCALE/Scaling Enable
> -	 * "When in Self Refresh Big FIFO mode, scaling enable will be
> -	 *  masked off while Big FIFO mode is exiting."
> -	 *
> -	 * Despite the w/a only being listed for IVB we assume that
> -	 * the ILK/SNB note has similar ramifications, hence we apply
> -	 * the w/a on all three platforms.
> -	 *
> -	 * With experimental results seems this is needed also for primary
> -	 * plane, not only sprite plane.
> -	 */
> -	if (plane->id != PLANE_CURSOR &&
> -	    (IS_IRONLAKE(dev_priv) || IS_SANDYBRIDGE(dev_priv) ||
> -	     IS_IVYBRIDGE(dev_priv)) &&
> -	    (turn_on || (!intel_plane_is_scaled(old_plane_state) &&
> -			 intel_plane_is_scaled(new_plane_state))))
> +	if ((IS_IRONLAKE(dev_priv) || IS_SANDYBRIDGE(dev_priv) ||
> IS_IVYBRIDGE(dev_priv)) &&
> +	    ilk_must_disable_lp_wm(new_crtc_state, old_plane_state,
> +new_plane_state))
>  		new_crtc_state->disable_lp_wm = true;
> 
>  	if (intel_plane_do_async_flip(plane, old_crtc_state, new_crtc_state)) {
> --
> 2.43.2