Re: [Y2038] [PATCH] drm/sti: Use 64-bit timestamps

From	Arnd Bergmann <arnd@arndb.de>
Newsgroups	linux.kernel
Subject	Re: [Y2038] [PATCH] drm/sti: Use 64-bit timestamps
Date	2016-04-18 12:40 +0200
Message-ID	<rpeL1-3XZ-23@gated-at.bofh.it> (permalink)
References	<rnrt1-BH-55@gated-at.bofh.it> <roHYK-35i-15@gated-at.bofh.it> <rpehY-3HT-35@gated-at.bofh.it>
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On Monday 18 April 2016 12:02:35 Vincent ABRIOU wrote:
> 
> getrawmonotonic comes from a legacy code so the use is not intentional.
> Honestly, it is not clear to me the difference between monotonic and 
> rawmonotonic. But in the debug context in which it is used, ktime_get 
> and ktime_get_raw will deliver the same level of information we need. So 
> implementation done by Tina is fine for me.
> 

Ok, cool, thanks for confirming!

FWIW, the best way I can see for illustrating the difference is that
rawmonotonic time is for things that should be synchronized with the
machines clock generators (e.g. A/V sync), while monotonic time is
for the case where you want to synchronize with another machine (or
the internet) that may have a slightly different clock generator but
uses NTP to correct for that.

In most cases the difference is irrelevant and we tend to use monotonic
time by default.

	Arnd

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Re: [Y2038] [PATCH] drm/sti: Use 64-bit timestamps Arnd Bergmann <arnd@arndb.de> - 2016-04-17 01:40 +0200
  Re: [Y2038] [PATCH] drm/sti: Use 64-bit timestamps Vincent ABRIOU <vincent.abriou@st.com> - 2016-04-18 12:10 +0200
    Re: [Y2038] [PATCH] drm/sti: Use 64-bit timestamps Arnd Bergmann <arnd@arndb.de> - 2016-04-18 12:40 +0200

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