[PATCH v2 07/11] drm/i915/psr: Check if resolution is supported by default SU granularity

[José Roberto de Souza]

Selective updates have a default granularity requirements as stated
by eDP spec, so check if HW can match those requirements before
enable PSR2.

Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan at intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
Signed-off-by: José Roberto de Souza <jose.souza at intel.com>
---
 drivers/gpu/drm/i915/intel_psr.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_psr.c b/drivers/gpu/drm/i915/intel_psr.c
index c4a8f476eea9..282ff1bc68a7 100644
--- a/drivers/gpu/drm/i915/intel_psr.c
+++ b/drivers/gpu/drm/i915/intel_psr.c
@@ -539,6 +539,18 @@ static bool intel_psr2_config_valid(struct intel_dp *intel_dp,
 		return false;
 	}
 
+	/* HW will always send full lines in SU blocks, so X will
+	 * always be 0 and we only need to check the width to validate
+	 * horizontal granularity.
+	 * About vertical granularity HW works by SU blocks starting
+	 * at each 4 lines with height of 4 lines, what eDP states
+	 * that sink should support.
+	 */
+	if (crtc_hdisplay % 4) {
+		DRM_DEBUG_KMS("PSR2 not enabled, default SU granularity not match\n");
+		return false;
+	}
+
 	return true;
 }
 
-- 
2.19.2