| From b4f711ee03d28f776fd2324fd0bd999cc428e4d2 Mon Sep 17 00:00:00 2001 |
| From: John Stultz <john.stultz@linaro.org> |
| Date: Wed, 24 Apr 2013 11:32:56 -0700 |
| Subject: time: Revert ALWAYS_USE_PERSISTENT_CLOCK compile time optimizaitons |
| |
| From: John Stultz <john.stultz@linaro.org> |
| |
| 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> |
| |
| --- |
| arch/x86/Kconfig | 1 - |
| drivers/rtc/Kconfig | 2 -- |
| include/linux/time.h | 4 ---- |
| kernel/time/Kconfig | 5 ----- |
| 4 files changed, 12 deletions(-) |
| |
| --- 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 |
| --- 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 |
| --- a/include/linux/time.h |
| +++ b/include/linux/time.h |
| @@ -117,14 +117,10 @@ static inline bool timespec_valid_strict |
| |
| 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); |
| --- 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 |
