Re: [Intel-gfx] [PATCH] drm/i915: Skip wm/ddb readout for disabled pipes

["Lisovskiy, Stanislav" <stanislav.lisovskiy@intel.com>]

On Fri, Jun 17, 2022 at 10:59:48PM +0300, Ville Syrjala wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> 
> The stuff programmed into the wm/ddb registers of planes
> on disabled pipes doesn't matter. So during readout just
> leave our software state tracking for those zeroed.
> 
> This should avoid us trying too hard to clean up after
> whatever mess the VBIOS/GOP left in there. The actual
> hardware state will get cleaned up if/when we enable
> the pipe anyway.
> 
> References: https://gitlab.freedesktop.org/drm/intel/-/issues/5711
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

Reviewed-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>

> ---
>  drivers/gpu/drm/i915/intel_pm.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> index 174fab564d10..d083964d5470 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -6560,7 +6560,10 @@ void skl_wm_get_hw_state(struct drm_i915_private *dev_priv)
>  		enum plane_id plane_id;
>  		u8 slices;
>  
> -		skl_pipe_wm_get_hw_state(crtc, &crtc_state->wm.skl.optimal);
> +		memset(&crtc_state->wm.skl.optimal, 0,
> +		       sizeof(crtc_state->wm.skl.optimal));
> +		if (crtc_state->hw.active)
> +			skl_pipe_wm_get_hw_state(crtc, &crtc_state->wm.skl.optimal);
>  		crtc_state->wm.skl.raw = crtc_state->wm.skl.optimal;
>  
>  		memset(&dbuf_state->ddb[pipe], 0, sizeof(dbuf_state->ddb[pipe]));
> @@ -6571,6 +6574,9 @@ void skl_wm_get_hw_state(struct drm_i915_private *dev_priv)
>  			struct skl_ddb_entry *ddb_y =
>  				&crtc_state->wm.skl.plane_ddb_y[plane_id];
>  
> +			if (!crtc_state->hw.active)
> +				continue;
> +
>  			skl_ddb_get_hw_plane_state(dev_priv, crtc->pipe,
>  						   plane_id, ddb, ddb_y);
>  
> -- 
> 2.35.1
>