On Tue, 16 Apr 2019 15:35:45 +0300 Pekka Paalanen <[email protected]> wrote:
> On Tue, 16 Apr 2019 13:14:58 +0200 > Erwin Burema <[email protected]> wrote: > > > On Tue, 16 Apr 2019 at 12:51, Pekka Paalanen <[email protected]> wrote: > > > > > > On Sun, 14 Apr 2019 12:57:48 +0200 > > > Erwin Burema <[email protected]> wrote: > > > > > > > --- > > > > .../cm_wayland_calibration.xml | 106 ++++++++++++++++++ > > > Hi, > > > > > > would you not need a corresponding event to know the compositor has > > > shown the requested color? > > > > > > It could be as simple as a new_id argument with wl_callback interface. > > > > > > > Good point, will add that in the next version. Might also be an > > interesting way to measure GPU/display latency (time from callback > > received to actual change observed on screen although not sure how > > accurate that will be) > > Hi, > > the Wayland presentation-time extension is much better for latency > measurements as it delivers a flip timestamp hopefully from the > hardware. You can trivially compute the delay from client update to > hardware flip, and with a measurement device you can measure from flip > to light if you can synchronise the clocks. > > But to use that you need a wl_surface. Wayland presentation-time extension: https://gitlab.freedesktop.org/wayland/wayland-protocols/blob/master/stable/presentation-time/presentation-time.xml The relevant event is wp_presentation_feedback.presented. An example of a calibration extension that hijacks a whole output (and a specific input device) is here: https://gitlab.freedesktop.org/wayland/weston/blob/master/protocol/weston-touch-calibration.xml Thanks, pq
pgp5h77Ntpc7T.pgp
Description: OpenPGP digital signature
_______________________________________________ wayland-devel mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/wayland-devel
