drm/i915/psr: Check that vblank is long enough for psr2

Ensure vblank >= psr2 vblank
where
Psr2 vblank = PSR2_CTL Block Count Number maximum line count.

Bspec: 71580, 49274

v2: Use calculated block count number maximum line count
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/20230329150703.432072-6-jouni.hogander@intel.com

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

@@ -968,6 +968,15 @@ static bool intel_psr2_config_valid(struct intel_dp *intel_dp,
 		return false;
 	}
 
+	/* Vblank >= PSR2_CTL Block Count Number maximum line count */
+	if (crtc_state->hw.adjusted_mode.crtc_vblank_end -
+	    crtc_state->hw.adjusted_mode.crtc_vblank_start <
+	    psr2_block_count_lines(intel_dp)) {
+		drm_dbg_kms(&dev_priv->drm,
+			    "PSR2 not enabled, too short vblank time\n");
+		return false;
+	}
+
 	if (HAS_PSR2_SEL_FETCH(dev_priv)) {
 		if (!intel_psr2_sel_fetch_config_valid(intel_dp, crtc_state) &&
 		    !HAS_PSR_HW_TRACKING(dev_priv)) {