From: Karel Zak <kzak@redhat.com>
Date: Wed, 24 Jun 2026 11:29:16 +0000 (+0200)
Subject: hwclock, rtcwake: hint about uninitialized RTC on EINVAL
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=52161b408c6efb8d416d3602d72cd900d4ccc52d;p=thirdparty%2Futil-linux.git

hwclock, rtcwake: hint about uninitialized RTC on EINVAL

Some RTC drivers (e.g., rtc-nxp-bbnsm) return EINVAL from
RTC_RD_TIME when the hardware time counter has never been
initialized. Print a hint so users know the likely cause rather
than just seeing "Invalid argument".

Addresses: https://github.com/util-linux/util-linux/pull/4376

Signed-off-by: Karel Zak <kzak@redhat.com>
---

diff --git a/sys-utils/hwclock-rtc.c b/sys-utils/hwclock-rtc.c
index f8518c30c..1b82b77b4 100644
--- a/sys-utils/hwclock-rtc.c
+++ b/sys-utils/hwclock-rtc.c
@@ -157,8 +157,11 @@ static int do_rtc_read_ioctl(int rtc_fd, struct tm *tm)
 	rc = ioctl(rtc_fd, RTC_RD_TIME, &rtc_tm);
 
 	if (rc == -1) {
+		int errsv = errno;
 		warn(_("ioctl(RTC_RD_TIME) to %s to read the time failed"),
 			rtc_dev_name);
+		if (errsv == EINVAL)
+			warnx(_("RTC may not be initialized"));
 		return -1;
 	}
 
diff --git a/sys-utils/rtcwake.c b/sys-utils/rtcwake.c
index ad5135644..0a3bf8e05 100644
--- a/sys-utils/rtcwake.c
+++ b/sys-utils/rtcwake.c
@@ -174,7 +174,10 @@ static int get_basetimes(struct rtcwake_control *ctl, int fd)
 	 * precisely (+/- a second) as we can read them.
 	 */
 	if (ioctl(fd, RTC_RD_TIME, &rtc) < 0) {
+		int errsv = errno;
 		warn(_("read rtc time failed"));
+		if (errsv == EINVAL)
+			warnx(_("RTC may not be initialized"));
 		return -1;
 	}