[Intel-gfx] [PATCH v4 4/5] drm/i915/psr: Check that vblank is long enough for psr2

["Jouni Högander" <jouni.hogander@intel.com>]

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>
---
 drivers/gpu/drm/i915/display/intel_psr.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_psr.c b/drivers/gpu/drm/i915/display/intel_psr.c
index 4b7c946a9a25..b53c71c06105 100644
--- a/drivers/gpu/drm/i915/display/intel_psr.c
+++ b/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)) {
-- 
2.34.1