Commit cef9ecc8 authored by Mario Limonciello's avatar Mario Limonciello Committed by Alexandre Belloni
Browse files

rtc: Extend timeout for waiting for UIP to clear to 1s 



Specs don't say anything about UIP being cleared within 10ms. They
only say that UIP won't occur for another 244uS. If a long NMI occurs
while UIP is still updating it might not be possible to get valid
data in 10ms.

This has been observed in the wild that around s2idle some calls can
take up to 480ms before UIP is clear.

Adjust callers from outside an interrupt context to wait for up to a
1s instead of 10ms.

Cc:  <stable@vger.kernel.org> # 6.1.y
Fixes: ec5895c0 ("rtc: mc146818-lib: extract mc146818_avoid_UIP")
Reported-by: default avatarCarsten Hatger <xmb8dsv4@gmail.com>
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217626


Tested-by: default avatarMateusz Jończyk <mat.jonczyk@o2.pl>
Reviewed-by: default avatarMateusz Jończyk <mat.jonczyk@o2.pl>
Acked-by: default avatarMateusz Jończyk <mat.jonczyk@o2.pl>
Signed-off-by: default avatarMario Limonciello <mario.limonciello@amd.com>
Link: https://lore.kernel.org/r/20231128053653.101798-5-mario.limonciello@amd.com


Signed-off-by: default avatarAlexandre Belloni <alexandre.belloni@bootlin.com>
parent 120931db

arch/x86/kernel/rtc.c

+1 −1
Original line number Diff line number Diff line
@@ -67,7 +67,7 @@ void mach_get_cmos_time(struct timespec64 *now) 
		return;

	}



	if (mc146818_get_time(&tm, 10)) {

	if (mc146818_get_time(&tm, 1000)) {

		pr_err("Unable to read current time from RTC\n");

		now->tv_sec = now->tv_nsec = 0;

		return;

drivers/base/power/trace.c

+1 −1
Original line number Diff line number Diff line
@@ -120,7 +120,7 @@ static unsigned int read_magic_time(void) 
	struct rtc_time time;

	unsigned int val;



	if (mc146818_get_time(&time, 10) < 0) {

	if (mc146818_get_time(&time, 1000) < 0) {

		pr_err("Unable to read current time from RTC\n");

		return 0;

	}

drivers/rtc/rtc-cmos.c

+1 −1
Original line number Diff line number Diff line
@@ -231,7 +231,7 @@ static int cmos_read_time(struct device *dev, struct rtc_time *t) 
	if (!pm_trace_rtc_valid())

		return -EIO;



	ret = mc146818_get_time(t, 10);

	ret = mc146818_get_time(t, 1000);

	if (ret < 0) {

		dev_err_ratelimited(dev, "unable to read current time\n");

		return ret;

drivers/rtc/rtc-mc146818-lib.c

+1 −1
Original line number Diff line number Diff line
@@ -93,7 +93,7 @@ EXPORT_SYMBOL_GPL(mc146818_avoid_UIP); 
 */

bool mc146818_does_rtc_work(void)

{

	return mc146818_avoid_UIP(NULL, 10, NULL);

	return mc146818_avoid_UIP(NULL, 1000, NULL);

}

EXPORT_SYMBOL_GPL(mc146818_does_rtc_work);