drm/i915: remove unused i915->active_pipes

Apparently the last reader of i915->active_pipes was removed with commit
ef79d62b ("drm/i915: Encapsulate dbuf state handling harder"), and
now it's only ever written to. Remove it completely.

Cc: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210826141830.889-1-jani.nikula@intel.com

drivers/gpu/drm/i915/display/intel_display.c

@@ -3724,7 +3724,6 @@ static void intel_crtc_disable_noatomic(struct intel_crtc *crtc,
 
 	intel_display_power_put_all_in_set(dev_priv, &crtc->enabled_power_domains);
 
-	dev_priv->active_pipes &= ~BIT(pipe);
 	cdclk_state->min_cdclk[pipe] = 0;
 	cdclk_state->min_voltage_level[pipe] = 0;
 	cdclk_state->active_pipes &= ~BIT(pipe);
@@ -12180,8 +12179,7 @@ static void intel_modeset_readout_hw_state(struct drm_device *dev)
 			    enableddisabled(crtc_state->hw.active));
 	}
 
-	dev_priv->active_pipes = cdclk_state->active_pipes =
-		dbuf_state->active_pipes = active_pipes;
+	cdclk_state->active_pipes = dbuf_state->active_pipes = active_pipes;
 
 	readout_plane_state(dev_priv);
 

drivers/gpu/drm/i915/i915_drv.h

@@ -1015,12 +1015,6 @@ struct drm_i915_private {
 
 	struct list_head global_obj_list;
 
-	/*
-	 * For reading active_pipes holding any crtc lock is
-	 * sufficient, for writing must hold all of them.
-	 */
-	u8 active_pipes;
-
 	struct i915_wa_list gt_wa_list;
 
 	struct i915_frontbuffer_tracking fb_tracking;