Skip to content

Commit

Permalink
rtc: Extend timeout for waiting for UIP to clear to 1s
Browse files Browse the repository at this point in the history
commit cef9ecc upstream.

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: ec5895c ("rtc: mc146818-lib: extract mc146818_avoid_UIP")
Reported-by: Carsten Hatger <xmb8dsv4@gmail.com>
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217626
Tested-by: Mateusz Jończyk <mat.jonczyk@o2.pl>
Reviewed-by: Mateusz Jończyk <mat.jonczyk@o2.pl>
Acked-by: Mateusz Jończyk <mat.jonczyk@o2.pl>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Link: https://lore.kernel.org/r/20231128053653.101798-5-mario.limonciello@amd.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  • Loading branch information
superm1 authored and gregkh committed Feb 1, 2024
1 parent 0181f82 commit 3d049da
Show file tree
Hide file tree
Showing 4 changed files with 4 additions and 4 deletions.
2 changes: 1 addition & 1 deletion arch/x86/kernel/rtc.c
Original file line number Diff line number Diff line change
Expand Up @@ -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;
Expand Down
2 changes: 1 addition & 1 deletion drivers/base/power/trace.c
Original file line number Diff line number Diff line change
Expand Up @@ -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;
}
Expand Down
2 changes: 1 addition & 1 deletion drivers/rtc/rtc-cmos.c
Original file line number Diff line number Diff line change
Expand Up @@ -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;
Expand Down
2 changes: 1 addition & 1 deletion drivers/rtc/rtc-mc146818-lib.c
Original file line number Diff line number Diff line change
Expand Up @@ -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);

Expand Down

0 comments on commit 3d049da

Please sign in to comment.