drm/i915: Preallocate the debug power domain wakerefs array

Since the current size of intel_display_power_domain_set struct is
close to 1kB, it's better to use preallocated memory for it. The only
user of the intel_display_power_get/put_in_set() allocating the struct
on stack is hsw_get_pipe_config(), so we can avoid potential stack
overallocations by moving the struct here to the preallocated
intel_crtc struct (hsw_get_pipe_config() is non-reentrant wrt. each
CRTC).

This patch replaces
https://lore.kernel.org/intel-gfx/[email protected]/T/#md3f6cdf17fcd

Suggested-by: Ville Syrjälä <[email protected]>
Cc: Ville Syrjälä <[email protected]>
Cc: Jani Nikula <[email protected]>
Signed-off-by: Imre Deak <[email protected]>
Reviewed-by: Ville Syrjälä <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]

Author: ideak

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

@@ -4051,20 +4051,19 @@ static bool hsw_get_pipe_config(struct intel_crtc *crtc,
 				struct intel_crtc_state *pipe_config)
 {
 	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
-	struct intel_display_power_domain_set power_domain_set = { };
 	bool active;
 	u32 tmp;
 
-	if (!intel_display_power_get_in_set_if_enabled(dev_priv, &power_domain_set,
+	if (!intel_display_power_get_in_set_if_enabled(dev_priv, &crtc->hw_readout_power_domains,
 						       POWER_DOMAIN_PIPE(crtc->pipe)))
 		return false;
 
 	pipe_config->shared_dpll = NULL;
 
-	active = hsw_get_transcoder_state(crtc, pipe_config, &power_domain_set);
+	active = hsw_get_transcoder_state(crtc, pipe_config, &crtc->hw_readout_power_domains);
 
 	if ((IS_GEMINILAKE(dev_priv) || IS_BROXTON(dev_priv)) &&
-	    bxt_get_dsi_transcoder_state(crtc, pipe_config, &power_domain_set)) {
+	    bxt_get_dsi_transcoder_state(crtc, pipe_config, &crtc->hw_readout_power_domains)) {
 		drm_WARN_ON(&dev_priv->drm, active);
 		active = true;
 	}
@@ -4123,7 +4122,7 @@ static bool hsw_get_pipe_config(struct intel_crtc *crtc,
 		pipe_config->ips_linetime =
 			REG_FIELD_GET(HSW_IPS_LINETIME_MASK, tmp);
 
-	if (intel_display_power_get_in_set_if_enabled(dev_priv, &power_domain_set,
+	if (intel_display_power_get_in_set_if_enabled(dev_priv, &crtc->hw_readout_power_domains,
 						      POWER_DOMAIN_PIPE_PANEL_FITTER(crtc->pipe))) {
 		if (DISPLAY_VER(dev_priv) >= 9)
 			skl_get_pfit_config(pipe_config);
@@ -4154,7 +4153,7 @@ static bool hsw_get_pipe_config(struct intel_crtc *crtc,
 	}
 
 out:
-	intel_display_power_put_all_in_set(dev_priv, &power_domain_set);
+	intel_display_power_put_all_in_set(dev_priv, &crtc->hw_readout_power_domains);
 
 	return active;
 }

drivers/gpu/drm/i915/display/intel_display_types.h

@@ -1375,6 +1375,7 @@ struct intel_crtc {
 	u16 vmax_vblank_start;
 
 	struct intel_display_power_domain_set enabled_power_domains;
+	struct intel_display_power_domain_set hw_readout_power_domains;
 	struct intel_overlay *overlay;
 
 	struct intel_crtc_state *config;