From 2babfa062572b93ad11923ec5aaa343491ac18e7 Mon Sep 17 00:00:00 2001
From: Dave <dave.wang@emc.com.tw>
Date: Tue, 9 Apr 2019 02:30:07 -0400
Subject: [PATCH] elan: Simplify calibration check for ELAN_0C42

Check for the mean calibration being outside of range to know whether we
require a recalibration. Continue with the usual checks if the
calibration value is within range.
---
 libfprint/drivers/elan.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/libfprint/drivers/elan.c b/libfprint/drivers/elan.c
index 1299795..3314d8d 100644
--- a/libfprint/drivers/elan.c
+++ b/libfprint/drivers/elan.c
@@ -603,6 +603,14 @@ static int elan_need_calibration(struct elan_dev *elandev)
 
 	g_assert(frame_size != 0);
 
+	if (elandev->dev_type == ELAN_0C42) {
+		if (calib_mean > 5500 ||
+		    calib_mean < 2500) {
+			fp_dbg("Forcing needed recalibration");
+			return 1;
+		}
+	}
+
 	for (int i = 0; i < frame_size; i++)
 		bg_mean += elandev->background[i];
 	bg_mean /= frame_size;