From 493715f9b8173da8a1ca8af12a22eb1ded79d4eb Mon Sep 17 00:00:00 2001
From: Ahmad Khalifa <ahmadkhalifa570@gmail.com>
Date: Fri, 19 Apr 2024 16:43:19 -0600
Subject: [PATCH] ig4_iic: Warn on NACK

Some DSDTs define non-existent devices, warn the user when an access is attempted on one of these devices.

Reviewed by: imp, markj, Elliott Mitchell
Pull Request: https://github.com/freebsd/freebsd-src/pull/1125
---
 sys/dev/ichiic/ig4_iic.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/sys/dev/ichiic/ig4_iic.c b/sys/dev/ichiic/ig4_iic.c
index 98c160ec9fd2..652d5a084f8b 100644
--- a/sys/dev/ichiic/ig4_iic.c
+++ b/sys/dev/ichiic/ig4_iic.c
@@ -675,6 +675,10 @@ ig4iic_transfer(device_t dev, struct iic_msg *msgs, uint32_t nmsgs)
 		rpstart = !stop;
 	}
 
+	if (error == IIC_ENOACK && bootverbose)
+		device_printf(dev, "Warning: NACK for slave address 0x%x\n",
+		    msgs[i].slave >> 1);
+
 	if (!allocated)
 		sx_unlock(&sc->call_lock);
 	return (error);