drm/i915/psr: Add intel_psr_needs_block_dc_vblank for blocking dc entry

We need to block DC6 entry in case of Panel Replay as enabling VBI doesn't
prevent it in case of Panel Replay. Panel Replay switches main link off on
DC entry. This means vblank interrupts are not fired and is a problem if
user-space is polling for vblank events. For this purpose add new function
to query need for dc entry blocking on.

Signed-off-by: Jouni Högander <jouni.hogander@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240920062340.1333777-2-jouni.hogander@intel.com

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

@@ -35,6 +35,7 @@
 #include "intel_cursor_regs.h"
 #include "intel_ddi.h"
 #include "intel_de.h"
+#include "intel_display_irq.h"
 #include "intel_display_types.h"
 #include "intel_dp.h"
 #include "intel_dp_aux.h"
@@ -2229,6 +2230,36 @@ void intel_psr_resume(struct intel_dp *intel_dp)
 	mutex_unlock(&psr->lock);
 }
 
+/**
+ * intel_psr_needs_block_dc_vblank - Check if block dc entry is needed
+ * @crtc_state: CRTC status
+ *
+ * We need to block DC6 entry in case of Panel Replay as enabling VBI doesn't
+ * prevent it in case of Panel Replay. Panel Replay switches main link off on
+ * DC entry. This means vblank interrupts are not fired and is a problem if
+ * user-space is polling for vblank events.
+ */
+bool intel_psr_needs_block_dc_vblank(const struct intel_crtc_state *crtc_state)
+{
+	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
+	struct intel_encoder *encoder;
+
+	for_each_encoder_on_crtc(crtc->base.dev, &crtc->base, encoder) {
+		struct intel_dp *intel_dp;
+
+		if (!intel_encoder_is_dp(encoder))
+			continue;
+
+		intel_dp = enc_to_intel_dp(encoder);
+
+		if (intel_dp_is_edp(intel_dp) &&
+		    CAN_PANEL_REPLAY(intel_dp))
+			return true;
+	}
+
+	return false;
+}
+
 static u32 man_trk_ctl_enable_bit_get(struct intel_display *display)
 {
 	struct drm_i915_private *dev_priv = to_i915(display->drm);

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

@@ -58,6 +58,7 @@ int intel_psr2_sel_fetch_update(struct intel_atomic_state *state,
 void intel_psr2_program_trans_man_trk_ctl(const struct intel_crtc_state *crtc_state);
 void intel_psr_pause(struct intel_dp *intel_dp);
 void intel_psr_resume(struct intel_dp *intel_dp);
+bool intel_psr_needs_block_dc_vblank(const struct intel_crtc_state *crtc_state);
 
 void intel_psr_lock(const struct intel_crtc_state *crtc_state);
 void intel_psr_unlock(const struct intel_crtc_state *crtc_state);