Three recent blog postings on DRI3000

[Keith Packard]

Maarten Lankhorst <maarten.lankhorst at canonical.com> writes:

> drm_calc_vbltimestamp_from_scanoutpos already uses CLOCK_MONOTONIC
> for the timestamps afaict. If you round to the nearest frame I don't see how you could
> possibly get glitches.

Because the display clock and the time clock are not slaved to each
other, so they will drift, possibly by quite a bit given the general
goal of using the cheapest components that meet the timing specs
everywhere. Plus, you'll presumably have NTP running, which will slew
even the monotonic clock rate around.

You'd have to constantly update your notion of the expected time for
each frame or you'd be off from time to time.

-- 
keith.packard at intel.com
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