[PATCH] clocksource: acpi_pm: fix return value of __setup handler

[Randy Dunlap]

__setup() handlers should return 1 to obsolete_checksetup() in
init/main.c to indicate that the boot option has been handled.
A return of 0 causes the boot option/value to be listed as an Unknown
kernel parameter and added to init's (limited) environment strings.

The __setup() handler interface isn't meant to handle negative return
values -- they are non-zero, so they mean "handled" (like a return
value of 1 does), but that's just a quirk. So return 1 from
parse_pmtmr(). Also print a warning message if kstrtouint() returns
an error.

Fixes: 60e3bf14d4e2 ("clocksource: clean up parse_pmtmr()")
Signed-off-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
From: Igor Zhbanov <i.zhbanov@xxxxxxxxxxxx>
Link: lore.kernel.org/r/64644a2f-4a20-bab3-1e15-3b2cdd0defe3@xxxxxxxxxxxx
Cc: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Cc: John Stultz <john.stultz@xxxxxxxxxx>
Cc: Daniel Lezcano <daniel.lezcano@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: "Rafael J. Wysocki" <rafael@xxxxxxxxxx>
---
 drivers/clocksource/acpi_pm.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

--- linux-next-20220308.orig/drivers/clocksource/acpi_pm.c
+++ linux-next-20220308/drivers/clocksource/acpi_pm.c
@@ -229,8 +229,10 @@ static int __init parse_pmtmr(char *arg)
 	int ret;
 
 	ret = kstrtouint(arg, 16, &base);
-	if (ret)
-		return ret;
+	if (ret) {
+		pr_warn("PMTMR: invalid 'pmtmr=' value: '%s'\n", arg);
+		return 1;
+	}
 
 	pr_info("PMTMR IOPort override: 0x%04x -> 0x%04x\n", pmtmr_ioport,
 		base);