Hi Arjan,
This is a patch (from AC kernel 3.0 tree) to fix bug 6762,
https://bugzilla.otcshare.org/show_bug.cgi?id=6762 .
pls review.
Thanks,
Feng
commit c48e317d5ca3715992be55897e829286c6c5e9b8
Author: Feng Tang <feng.t...@intel.com>
Date: Mon Jun 6 10:36:50 2011 +0100
vrtc: change its year offset from 1960 to 1972
Real world year equals the value in vrtc YEAR register plus an offset.
We used 1960 as the offset to make leap year consistent, but for a
device's first use, its YEAR register is 0 and the system year will
be parsed as 1960 which is not a valid UNIX time and will cause many
applications to fail mysteriously. So use 1972 instead to fix this
issue.
Updated patch which adds a sanity check suggested by Mathias
Signed-off-by: Feng Tang <feng.t...@intel.com>
Signed-off-by: Alan Cox <a...@linux.intel.com>
diff --git a/arch/x86/platform/mrst/vrtc.c b/arch/x86/platform/mrst/vrtc.c
index 73d70d6..34d6055 100644
--- a/arch/x86/platform/mrst/vrtc.c
+++ b/arch/x86/platform/mrst/vrtc.c
@@ -70,8 +70,8 @@ unsigned long vrtc_get_time(void)
mon = vrtc_cmos_read(RTC_MONTH);
year = vrtc_cmos_read(RTC_YEAR);
- /* vRTC YEAR reg contains the offset to 1960 */
- year += 1960;
+ /* vRTC YEAR reg contains the offset to 1972 */
+ year += 1972;
printk(KERN_INFO "vRTC: sec: %d min: %d hour: %d day: %d "
"mon: %d year: %d\n", sec, min, hour, mday, mon, year);
diff --git a/drivers/rtc/rtc-mrst.c b/drivers/rtc/rtc-mrst.c
index 6b003f5..be276db 100644
--- a/drivers/rtc/rtc-mrst.c
+++ b/drivers/rtc/rtc-mrst.c
@@ -76,12 +76,15 @@ static inline unsigned char vrtc_is_updating(void)
/*
* rtc_time's year contains the increment over 1900, but vRTC's YEAR
* register can't be programmed to value larger than 0x64, so vRTC
- * driver chose to use 1960 (1970 is UNIX time start point) as the base,
+ * driver chose to use 1972 (1970 is UNIX time start point) as the base,
* and does the translation at read/write time.
*
- * Why not just use 1970 as the offset? it's because using 1960 will
+ * Why not just use 1970 as the offset? it's because using 1972 will
* make it consistent in leap year setting for both vrtc and low-level
- * physical rtc devices.
+ * physical rtc devices. Then why not use 1960 as the offset? If we use
+ * 1960, for a device's first use, its YEAR register is 0 and the system
+ * year will be parsed as 1960 which is not a valid UNIX time and will
+ * cause many applications to fail mysteriously.
*/
static int mrst_read_time(struct device *dev, struct rtc_time *time)
{
@@ -99,10 +102,10 @@ static int mrst_read_time(struct device *dev, struct
rtc_time *time)
time->tm_year = vrtc_cmos_read(RTC_YEAR);
spin_unlock_irqrestore(&rtc_lock, flags);
- /* Adjust for the 1960/1900 */
- time->tm_year += 60;
+ /* Adjust for the 1972/1900 */
+ time->tm_year += 72;
time->tm_mon--;
- return RTC_24H;
+ return rtc_valid_tm(time);
}
static int mrst_set_time(struct device *dev, struct rtc_time *time)
@@ -119,9 +122,9 @@ static int mrst_set_time(struct device *dev, struct
rtc_time *time)
min = time->tm_min;
sec = time->tm_sec;
- if (yrs < 70 || yrs > 138)
+ if (yrs < 72 || yrs > 138)
return -EINVAL;
- yrs -= 60;
+ yrs -= 72;
spin_lock_irqsave(&rtc_lock, flags);
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