From 14cc4f1ba2dfed4c943f7634490931f13c24c210 Mon Sep 17 00:00:00 2001
From: Antonio Ospite <antonio.ospite@collabora.com>
Date: Fri, 12 Nov 2021 18:40:57 +0100
Subject: [PATCH] d/v4l2: fix building with older linux kernel like 4.15

Older linux kernels like 4.15 don't have V4L2_CID_DIGITAL_GAIN or
V4L2_CTRL_FLAG_MODIFY_LAYOUT, add conditional guards to build
successfully on systems with such kernels.
---
 src/xrt/drivers/v4l2/v4l2_driver.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/xrt/drivers/v4l2/v4l2_driver.c b/src/xrt/drivers/v4l2/v4l2_driver.c
index b92abffc1..1ab06b0f2 100644
--- a/src/xrt/drivers/v4l2/v4l2_driver.c
+++ b/src/xrt/drivers/v4l2/v4l2_driver.c
@@ -1015,7 +1015,9 @@ dump_contron_name(uint32_t id)
 		CASE(EXPOSURE);
 		CASE(AUTOGAIN);
 		CASE(GAIN);
+#ifdef V4L2_CID_DIGITAL_GAIN
 		CASE(DIGITAL_GAIN);
+#endif
 		CASE(ANALOGUE_GAIN);
 		CASE(HFLIP);
 		CASE(VFLIP);
@@ -1096,7 +1098,9 @@ dump_controls(struct v4l2_fs *vid)
 		V_CHECK(VOLATILE);
 		V_CHECK(HAS_PAYLOAD);
 		V_CHECK(EXECUTE_ON_WRITE);
+#ifdef V4L2_CTRL_FLAG_MODIFY_LAYOUT
 		V_CHECK(MODIFY_LAYOUT);
+#endif
 #undef V_CHECK
 
 		U_LOG_E(" ");