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author | Dave Airlie <airlied@redhat.com> | 2013-11-08 06:34:39 (GMT) |
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committer | Dave Airlie <airlied@redhat.com> | 2013-11-08 06:34:39 (GMT) |
commit | 91915260ea5ed9d9b19bfb75d53c989c8ada2ab0 (patch) | |
tree | f7eb16ced65f39ebd0bb32e3b4e5e0f365755536 /kernel/time/clockevents.c | |
parent | 21136946c495b0e1e0f7e25a8de6f170efbdeadf (diff) | |
parent | 07bf139b906013ecef0c5e0441564d1ae10e974a (diff) | |
download | linux-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.c | 65 |
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); } /** |