drm/i915: Fix the MST PBN divider calculation

[linux-2.6-microblaze.git] / drivers / rtc / rtc-mc146818-lib.c

diff --git a/drivers/rtc/rtc-mc146818-lib.c b/drivers/rtc/rtc-mc146818-lib.c
index 972a5b9..f83c138 100644 (file)
--- a/drivers/rtc/rtc-mc146818-lib.c
+++ b/drivers/rtc/rtc-mc146818-lib.c
@@ -21,6 +21,13 @@ unsigned int mc146818_get_time(struct rtc_time *time)
 
 again:
        spin_lock_irqsave(&rtc_lock, flags);
+       /* Ensure that the RTC is accessible. Bit 0-6 must be 0! */
+       if (WARN_ON_ONCE((CMOS_READ(RTC_VALID) & 0x7f) != 0)) {
+               spin_unlock_irqrestore(&rtc_lock, flags);
+               memset(time, 0xff, sizeof(*time));
+               return 0;
+       }
+
        /*
         * Check whether there is an update in progress during which the
         * readout is unspecified. The maximum update time is ~2ms. Poll