aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorJohn Stultz <john.stultz@linaro.org>2013-04-24 11:32:56 -0700
committerThomas Gleixner <tglx@linutronix.de>2013-05-14 20:54:06 +0200
commitb4f711ee03d28f776fd2324fd0bd999cc428e4d2 (patch)
tree8d8b659c2514648be0bfe51f0de65110da008f22
parent42a5cf46cd56f46267d2a9fcf2655f4078cd3042 (diff)
time: Revert ALWAYS_USE_PERSISTENT_CLOCK compile time optimizaitons
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: stable <stable@vger.kernel.org> #3.9 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>
-rw-r--r--arch/x86/Kconfig1
-rw-r--r--drivers/rtc/Kconfig2
-rw-r--r--include/linux/time.h4
-rw-r--r--kernel/time/Kconfig5
4 files changed, 0 insertions, 12 deletions
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 5db2117ae28..45c41249321 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -108,7 +108,6 @@ 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 0c81915b199..b9838130a7b 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 22d81b3c955..d5d229b2e5a 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