The patch titled
rtc: fix readback from /sys/class/rtc/rtc?/wakealarm
has been removed from the -mm tree. Its filename was
rtc-fix-readback-from-sys-class-rtc-rtc-wakealarm.patch
This patch was dropped because an updated version will be merged
------------------------------------------------------
Subject: rtc: fix readback from /sys/class/rtc/rtc?/wakealarm
From: Mark Lord <lkml@xxxxxx>
Fix /sys/class/rtc/rtc?/wakealarm so that readback values now agree with
the written values.
Signed-off-by: Mark Lord <mlord@xxxxxxxxx>
Cc: David Brownell <david-b@xxxxxxxxxxx>
Cc: Alessandro Zummo <a.zummo@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
diff -puN drivers/rtc/rtc-sysfs.c~rtc-fix-readback-from-sys-class-rtc-rtc-wakealarm drivers/rtc/rtc-sysfs.c
--- a/drivers/rtc/rtc-sysfs.c~rtc-fix-readback-from-sys-class-rtc-rtc-wakealarm
+++ a/drivers/rtc/rtc-sysfs.c
@@ -88,6 +88,9 @@ rtc_sysfs_show_wakealarm(struct device *
ssize_t retval;
unsigned long alarm;
struct rtc_wkalrm alm;
+ struct rtc_time before, now;
+ struct rtc_device *rtc = to_rtc_device(dev);
+ int first_time = 1;
/* Don't show disabled alarms; but the RTC could leave the
* alarm enabled after it's already triggered. Alarms are
@@ -97,13 +100,68 @@ rtc_sysfs_show_wakealarm(struct device *
* REVISIT maybe we should require RTC implementations to
* disable the RTC alarm after it triggers, for uniformity.
*/
- retval = rtc_read_alarm(to_rtc_device(dev), &alm);
- if (retval == 0 && alm.enabled) {
- rtc_tm_to_time(&alm.time, &alarm);
- retval = sprintf(buf, "%lu\n", alarm);
- }
- return retval;
+ /* The lower level RTC driver may not be capable of filling
+ * in all fields of the rtc_time struct (eg. rtc-cmos),
+ * and so might instead return -1 in some fields.
+ * We deal with that here by grabbing a current timestamp
+ * and using values from that for any missing (-1) values.
+ *
+ * But this could be racey, in that some fields might wrap
+ * to a new day/month/year/etc.. between reading the time
+ * and then reading the alarm (which internally may also
+ * read the time).
+ *
+ * So we read the time *again* afterward, and if the two
+ * timestamps differ then we know we need to repeat the
+ * procedure to avoid any field wrap issues.
+ *
+ * This could all instead be done in the lower level driver,
+ * but if more than one RTC implementation needs it,
+ * then it might be best to leave it here.
+ */
+
+ /* get the "before" timestamp */
+ retval = rtc_read_time(rtc, &before);
+ if (retval < 0)
+ return retval;
+ do {
+ if (!first_time)
+ memcpy(&before, &now, sizeof(struct rtc_time));
+ first_time = 0;
+
+ /* get the RTC alarm values, which may be incomplete */
+ retval = rtc_read_alarm(to_rtc_device(dev), &alm);
+ if (retval)
+ return retval;
+ if (!alm.enabled)
+ return 0;
+
+ /* get the "after" timestamp, to detect wrapped fields */
+ retval = rtc_read_time(rtc, &now);
+ if (retval < 0)
+ return retval;
+
+ } while ( before.tm_hour != now.tm_hour
+ || before.tm_mday != now.tm_mday
+ || before.tm_mon != now.tm_mon
+ || before.tm_year != now.tm_year
+ || before.tm_isdst != now.tm_isdst);
+
+ /* fill in missing alarm fields using the timestamp */
+ if (alm.time.tm_hour == -1)
+ alm.time.tm_hour = now.tm_hour;
+ if (alm.time.tm_mday == -1)
+ alm.time.tm_mday = now.tm_mday;
+ if (alm.time.tm_mon == -1)
+ alm.time.tm_mon = now.tm_mon;
+ if (alm.time.tm_year == -1)
+ alm.time.tm_year = now.tm_year;
+ if (alm.time.tm_isdst == -1)
+ alm.time.tm_yday = now.tm_isdst;
+
+ rtc_tm_to_time(&alm.time, &alarm);
+ return sprintf(buf, "%lu\n", alarm);
}
static ssize_t
_
Patches currently in -mm which might be from lkml@xxxxxx are
rtc-fix-readback-from-sys-class-rtc-rtc-wakealarm.patch
-
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