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authorDave Airlie <airlied@redhat.com>2013-11-08 06:34:39 (GMT)
committerDave Airlie <airlied@redhat.com>2013-11-08 06:34:39 (GMT)
commit91915260ea5ed9d9b19bfb75d53c989c8ada2ab0 (patch)
treef7eb16ced65f39ebd0bb32e3b4e5e0f365755536 /kernel/time/clockevents.c
parent21136946c495b0e1e0f7e25a8de6f170efbdeadf (diff)
parent07bf139b906013ecef0c5e0441564d1ae10e974a (diff)
downloadlinux-91915260ea5ed9d9b19bfb75d53c989c8ada2ab0.tar.xz
Merge tag 'drm-intel-fixes-2013-11-07' of git://people.freedesktop.org/~danvet/drm-intel into drm-next
Bit a bit -fixes pull request in the merge window than usual dua to two feauture-y things: - Display CRCs are now enabled on all platforms, including the odd DP case on gm45/vlv. Since this is a testing-only feature it should ever hurt, but I figured it'll help with regression-testing -fixes. So I left it in and didn't postpone it to 3.14. - Display power well refactoring from Imre. Would have caused major pain conflict with the bdw stage 1 patches if I'd postpone this to -next. It's only an relatively small interface rework, so shouldn't cause pain. It's also been in my tree since almost 3 weeks already. That accounts for about two thirds of the pull, otherwise just bugfixes: - vlv backlight fix from Jesse/Jani - vlv vblank timestamp fix from Jesse - improved edp detection through vbt from Ville (fixes a vlv issue) - eDP vdd fix from Paulo - fixes for dvo lvds on i830M - a few smaller things all over Note: This contains a backmerge of v3.12. Since the -internal branch always applied on top of -nightly I need that unified base to merge bdw patches. So you'll get a conflict with radeon connector props when pulling this (and nouveau/master will also conflict a bit when Ben doesn't rebase). The backmerge itself only had conflicts in drm/i915. There's also a tiny conflict between Jani's backlight fix and your sysfs lifetime fix in drm-next. * tag 'drm-intel-fixes-2013-11-07' of git://people.freedesktop.org/~danvet/drm-intel: (940 commits) drm/i915/vlv: use per-pipe backlight controls v2 drm/i915: make backlight functions take a connector drm/i915: move opregion asle request handling to a work queue drm/i915/vlv: use PIPE_START_VBLANK interrupts on VLV drm/i915: Make intel_dp_is_edp() less specific drm/i915: Give names to the VBT child device type bits drm/i915/vlv: enable HDA display audio for Valleyview2 drm/i915/dvo: call ->mode_set callback only when the port is running drm/i915: avoid unclaimed registers when capturing the error state drm/i915: Enable DP port CRC for the "auto" source on g4x/vlv drm/i915: scramble reset support for DP port CRC on vlv drm/i915: scramble reset support for DP port CRC on g4x drm/i916: add "auto" pipe CRC source ... Conflicts: MAINTAINERS drivers/gpu/drm/i915/intel_panel.c drivers/gpu/drm/nouveau/core/subdev/mc/base.c drivers/gpu/drm/radeon/atombios_encoders.c drivers/gpu/drm/radeon/radeon_connectors.c
Diffstat (limited to 'kernel/time/clockevents.c')
-rw-r--r--kernel/time/clockevents.c65
1 files changed, 50 insertions, 15 deletions
diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c
index 38959c8..662c579 100644
--- a/kernel/time/clockevents.c
+++ b/kernel/time/clockevents.c
@@ -33,29 +33,64 @@ struct ce_unbind {
int res;
};
-/**
- * clockevents_delta2ns - Convert a latch value (device ticks) to nanoseconds
- * @latch: value to convert
- * @evt: pointer to clock event device descriptor
- *
- * Math helper, returns latch value converted to nanoseconds (bound checked)
- */
-u64 clockevent_delta2ns(unsigned long latch, struct clock_event_device *evt)
+static u64 cev_delta2ns(unsigned long latch, struct clock_event_device *evt,
+ bool ismax)
{
u64 clc = (u64) latch << evt->shift;
+ u64 rnd;
if (unlikely(!evt->mult)) {
evt->mult = 1;
WARN_ON(1);
}
+ rnd = (u64) evt->mult - 1;
+
+ /*
+ * Upper bound sanity check. If the backwards conversion is
+ * not equal latch, we know that the above shift overflowed.
+ */
+ if ((clc >> evt->shift) != (u64)latch)
+ clc = ~0ULL;
+
+ /*
+ * Scaled math oddities:
+ *
+ * For mult <= (1 << shift) we can safely add mult - 1 to
+ * prevent integer rounding loss. So the backwards conversion
+ * from nsec to device ticks will be correct.
+ *
+ * For mult > (1 << shift), i.e. device frequency is > 1GHz we
+ * need to be careful. Adding mult - 1 will result in a value
+ * which when converted back to device ticks can be larger
+ * than latch by up to (mult - 1) >> shift. For the min_delta
+ * calculation we still want to apply this in order to stay
+ * above the minimum device ticks limit. For the upper limit
+ * we would end up with a latch value larger than the upper
+ * limit of the device, so we omit the add to stay below the
+ * device upper boundary.
+ *
+ * Also omit the add if it would overflow the u64 boundary.
+ */
+ if ((~0ULL - clc > rnd) &&
+ (!ismax || evt->mult <= (1U << evt->shift)))
+ clc += rnd;
do_div(clc, evt->mult);
- if (clc < 1000)
- clc = 1000;
- if (clc > KTIME_MAX)
- clc = KTIME_MAX;
- return clc;
+ /* Deltas less than 1usec are pointless noise */
+ return clc > 1000 ? clc : 1000;
+}
+
+/**
+ * clockevents_delta2ns - Convert a latch value (device ticks) to nanoseconds
+ * @latch: value to convert
+ * @evt: pointer to clock event device descriptor
+ *
+ * Math helper, returns latch value converted to nanoseconds (bound checked)
+ */
+u64 clockevent_delta2ns(unsigned long latch, struct clock_event_device *evt)
+{
+ return cev_delta2ns(latch, evt, false);
}
EXPORT_SYMBOL_GPL(clockevent_delta2ns);
@@ -380,8 +415,8 @@ void clockevents_config(struct clock_event_device *dev, u32 freq)
sec = 600;
clockevents_calc_mult_shift(dev, freq, sec);
- dev->min_delta_ns = clockevent_delta2ns(dev->min_delta_ticks, dev);
- dev->max_delta_ns = clockevent_delta2ns(dev->max_delta_ticks, dev);
+ dev->min_delta_ns = cev_delta2ns(dev->min_delta_ticks, dev, false);
+ dev->max_delta_ns = cev_delta2ns(dev->max_delta_ticks, dev, true);
}
/**