From ce31c1d704b6343cc095e5e57ded0e3c2467caad Mon Sep 17 00:00:00 2001
From: Dave <dave.wang@emc.com.tw>
Date: Tue, 9 Apr 2019 02:28:41 -0400
Subject: [PATCH] elan: Work-around one-byte responses being two-bytes long

On the ELAN_0C42 device, one-byte responses are 2 bytes long.
Adapt our expected response length.
---
 libfprint/drivers/elan.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/libfprint/drivers/elan.c b/libfprint/drivers/elan.c
index 3216bf1..46346be 100644
--- a/libfprint/drivers/elan.c
+++ b/libfprint/drivers/elan.c
@@ -383,6 +383,12 @@ static void elan_cmd_read(fpi_ssm *ssm, struct fp_img_dev *dev)
 		return;
 	}
 
+	if (elandev->dev_type == ELAN_0C42) {
+		/* ELAN_0C42 sends an extra byte in one byte responses */
+		if (elandev->cmd->response_len == 1)
+			response_len = 2;
+	}
+
 	if (elandev->cmd->cmd == get_image_cmd.cmd)
 		/* raw data has 2-byte "pixels" and the frame is vertical */
 		response_len =