diff options
Diffstat (limited to 'hwclock/hwclock.c')
| -rw-r--r-- | hwclock/hwclock.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/hwclock/hwclock.c b/hwclock/hwclock.c index 571d63fb..f691dfe5 100644 --- a/hwclock/hwclock.c +++ b/hwclock/hwclock.c @@ -1107,8 +1107,18 @@ determine_clock_access_method(const bool user_requests_ISA) { if (!ur) ur = probe_for_kd_clock(); + /* + * This final clause is a really bad idea on x86/AT PCs. You run the + * risk of a race condition with another copy of hwclock + * that already has /dev/rtc open. The fallback case on + * x86 is to then raise I/O priviledge level and access + * the RTC CMOS directly using I/O instructions. Simultaneous + * access like that can really hose the RTC. + */ +#if !defined(__i386__) if (!ur && !user_requests_ISA) ur = probe_for_cmos_clock(); +#endif if (debug) { if (ur) |