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authorMark Lord <lkml@rtr.ca>2007-11-03 22:04:03 -0400
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-11-04 13:13:09 -0800
commit615bb29ccbe9fa06d9f33b29d9c3f51340726656 (patch)
tree705059547b9564e8c57afb1645db04bc4b7e556c
parentb4f555081fdd27d13e6ff39d455d5aefae9d2c0c (diff)
rtc: ignore msb when reading back mday from alarm
I have a system here that actively relies upon RTC wake alarms, and it has been failing (again) for a few days when attempting to use the /sys/class/rtc/rtc?/wakealarm interface. The old (fixed by Linus) /proc/ interface still works, but I'd like to get it using the new one. This patch fixes rtc-cmos to ignore the two upper bits when reading the BCD mday (day of month) register from CMOS. Some systems (eg. mine) seem to have the top bit set to "1" for some reason. The older /proc/ interface ignores the upper bits, and so we should too. Signed-off-by: Mark Lord <mlord@pobox.com> Acked-by: David Brownell <david-b@pacbell.net> Cc: Alessandro Zummo <a.zummo@towertech.it> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--drivers/rtc/rtc-cmos.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/rtc/rtc-cmos.c b/drivers/rtc/rtc-cmos.c
index e3fe83a23cf..29cf1457ca1 100644
--- a/drivers/rtc/rtc-cmos.c
+++ b/drivers/rtc/rtc-cmos.c
@@ -120,7 +120,8 @@ static int cmos_read_alarm(struct device *dev, struct rtc_wkalrm *t)
t->time.tm_hour = CMOS_READ(RTC_HOURS_ALARM);
if (cmos->day_alrm) {
- t->time.tm_mday = CMOS_READ(cmos->day_alrm);
+ /* ignore upper bits on readback per ACPI spec */
+ t->time.tm_mday = CMOS_READ(cmos->day_alrm) & 0x3f;
if (!t->time.tm_mday)
t->time.tm_mday = -1;