diff options
| author | John Stultz <john.stultz@linaro.org> | 2013-04-24 11:32:56 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-05-19 11:38:24 -0700 |
| commit | d96ac6f2cda4c2e1c7773c37ce9017d3870be5bc (patch) | |
| tree | 60f44c401923e25335f4a84c4bd445188999361b | |
| parent | 93d927e2e81b0d0b2aa940c7a1ea62ba840d4924 (diff) | |
time: Revert ALWAYS_USE_PERSISTENT_CLOCK compile time optimizaitons
commit b4f711ee03d28f776fd2324fd0bd999cc428e4d2 upstream.
Kay Sievers noted that the ALWAYS_USE_PERSISTENT_CLOCK config,
which enables some minor compile time optimization to avoid
uncessary code in mostly the suspend/resume path could cause
problems for userland.
In particular, the dependency for RTC_HCTOSYS on
!ALWAYS_USE_PERSISTENT_CLOCK, which avoids setting the time
twice and simplifies suspend/resume, has the side effect
of causing the /sys/class/rtc/rtcN/hctosys flag to always be
zero, and this flag is commonly used by udev to setup the
/dev/rtc symlink to /dev/rtcN, which can cause pain for
older applications.
While the udev rules could use some work to be less fragile,
breaking userland should strongly be avoided. Additionally
the compile time optimizations are fairly minor, and the code
being optimized is likely to be reworked in the future, so
lets revert this change.
Reported-by: Kay Sievers <kay@vrfy.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Cc: Feng Tang <feng.tang@intel.com>
Cc: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Link: http://lkml.kernel.org/r/1366828376-18124-1-git-send-email-john.stultz@linaro.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | arch/x86/Kconfig | 1 | ||||
| -rw-r--r-- | drivers/rtc/Kconfig | 2 | ||||
| -rw-r--r-- | include/linux/time.h | 4 | ||||
| -rw-r--r-- | kernel/time/Kconfig | 5 |
4 files changed, 0 insertions, 12 deletions
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 15b5cef4aa3..6ef2a378e3a 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -107,7 +107,6 @@ config X86 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) select GENERIC_TIME_VSYSCALL if X86_64 select KTIME_SCALAR if X86_32 - select ALWAYS_USE_PERSISTENT_CLOCK select GENERIC_STRNCPY_FROM_USER select GENERIC_STRNLEN_USER select HAVE_CONTEXT_TRACKING if X86_64 diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig index 79fbe3832df..9e95473180e 100644 --- a/drivers/rtc/Kconfig +++ b/drivers/rtc/Kconfig @@ -20,7 +20,6 @@ if RTC_CLASS config RTC_HCTOSYS bool "Set system time from RTC on startup and resume" default y - depends on !ALWAYS_USE_PERSISTENT_CLOCK help If you say yes here, the system time (wall clock) will be set using the value read from a specified RTC device. This is useful to avoid @@ -29,7 +28,6 @@ config RTC_HCTOSYS config RTC_SYSTOHC bool "Set the RTC time based on NTP synchronization" default y - depends on !ALWAYS_USE_PERSISTENT_CLOCK help If you say yes here, the system time (wall clock) will be stored in the RTC specified by RTC_HCTOSYS_DEVICE approximately every 11 diff --git a/include/linux/time.h b/include/linux/time.h index d4835dfdf25..afcdc4bb93a 100644 --- a/include/linux/time.h +++ b/include/linux/time.h @@ -117,14 +117,10 @@ static inline bool timespec_valid_strict(const struct timespec *ts) extern bool persistent_clock_exist; -#ifdef ALWAYS_USE_PERSISTENT_CLOCK -#define has_persistent_clock() true -#else static inline bool has_persistent_clock(void) { return persistent_clock_exist; } -#endif extern void read_persistent_clock(struct timespec *ts); extern void read_boot_clock(struct timespec *ts); diff --git a/kernel/time/Kconfig b/kernel/time/Kconfig index 24510d84efd..b69692250af 100644 --- a/kernel/time/Kconfig +++ b/kernel/time/Kconfig @@ -12,11 +12,6 @@ config CLOCKSOURCE_WATCHDOG config ARCH_CLOCKSOURCE_DATA bool -# Platforms has a persistent clock -config ALWAYS_USE_PERSISTENT_CLOCK - bool - default n - # Timekeeping vsyscall support config GENERIC_TIME_VSYSCALL bool |