On Tue, Feb 21, 2023 at 3:20 PM Rob Clark <robdclark@xxxxxxxxx> wrote: > > On Tue, Feb 21, 2023 at 2:46 PM Ville Syrjälä > <ville.syrjala@xxxxxxxxxxxxxxx> wrote: > > > > On Tue, Feb 21, 2023 at 02:28:10PM -0800, Rob Clark wrote: > > > On Tue, Feb 21, 2023 at 1:48 PM Ville Syrjälä > > > <ville.syrjala@xxxxxxxxxxxxxxx> wrote: > > > > > > > > On Tue, Feb 21, 2023 at 11:39:40PM +0200, Ville Syrjälä wrote: > > > > > On Tue, Feb 21, 2023 at 11:54:55AM -0800, Rob Clark wrote: > > > > > > On Tue, Feb 21, 2023 at 5:01 AM Ville Syrjälä > > > > > > <ville.syrjala@xxxxxxxxxxxxxxx> wrote: > > > > > > > > > > > > > > On Tue, Feb 21, 2023 at 10:45:51AM +0200, Pekka Paalanen wrote: > > > > > > > > On Mon, 20 Feb 2023 07:55:41 -0800 > > > > > > > > Rob Clark <robdclark@xxxxxxxxx> wrote: > > > > > > > > > > > > > > > > > On Mon, Feb 20, 2023 at 1:08 AM Pekka Paalanen <ppaalanen@xxxxxxxxx> wrote: > > > > > > > > > > > > > > > > > > > > On Sat, 18 Feb 2023 13:15:53 -0800 > > > > > > > > > > Rob Clark <robdclark@xxxxxxxxx> wrote: > > > > > > > > > > > > > > > > > > > > > From: Rob Clark <robdclark@xxxxxxxxxxxx> > > > > > > > > > > > > > > > > > > > > > > Will be used in the next commit to set a deadline on fences that an > > > > > > > > > > > atomic update is waiting on. > > > > > > > > > > > > > > > > > > > > > > Signed-off-by: Rob Clark <robdclark@xxxxxxxxxxxx> > > > > > > > > > > > --- > > > > > > > > > > > drivers/gpu/drm/drm_vblank.c | 32 ++++++++++++++++++++++++++++++++ > > > > > > > > > > > include/drm/drm_vblank.h | 1 + > > > > > > > > > > > 2 files changed, 33 insertions(+) > > > > > > > > > > > > > > > > > > > > > > diff --git a/drivers/gpu/drm/drm_vblank.c b/drivers/gpu/drm/drm_vblank.c > > > > > > > > > > > index 2ff31717a3de..caf25ebb34c5 100644 > > > > > > > > > > > --- a/drivers/gpu/drm/drm_vblank.c > > > > > > > > > > > +++ b/drivers/gpu/drm/drm_vblank.c > > > > > > > > > > > @@ -980,6 +980,38 @@ u64 drm_crtc_vblank_count_and_time(struct drm_crtc *crtc, > > > > > > > > > > > } > > > > > > > > > > > EXPORT_SYMBOL(drm_crtc_vblank_count_and_time); > > > > > > > > > > > > > > > > > > > > > > +/** > > > > > > > > > > > + * drm_crtc_next_vblank_time - calculate the time of the next vblank > > > > > > > > > > > + * @crtc: the crtc for which to calculate next vblank time > > > > > > > > > > > + * @vblanktime: pointer to time to receive the next vblank timestamp. > > > > > > > > > > > + * > > > > > > > > > > > + * Calculate the expected time of the next vblank based on time of previous > > > > > > > > > > > + * vblank and frame duration > > > > > > > > > > > > > > > > > > > > Hi, > > > > > > > > > > > > > > > > > > > > for VRR this targets the highest frame rate possible for the current > > > > > > > > > > VRR mode, right? > > > > > > > > > > > > > > > > > > > > > > > > > > > > It is based on vblank->framedur_ns which is in turn based on > > > > > > > > > mode->crtc_clock. Presumably for VRR that ends up being a maximum? > > > > > > > > > > > > > > > > I don't know. :-) > > > > > > > > > > > > > > At least for i915 this will give you the maximum frame > > > > > > > duration. > > > > > > > > > > > > > > Also this does not calculate the the start of vblank, it > > > > > > > calculates the start of active video. > > > > > > > > > > > > AFAIU, vsync_end/vsync_start are in units of line, so I could do something like: > > > > > > > > > > > > vsync_lines = vblank->hwmode.vsync_end - vblank->hwmode.vsync_start; > > > > > > vsyncdur = ns_to_ktime(vblank->linedur_ns * vsync_lines); > > > > > > framedur = ns_to_ktime(vblank->framedur_ns); > > > > > > *vblanktime = ktime_add(*vblanktime, ktime_sub(framedur, vsyncdur)); > > > > > > > > > > Something like this should work: > > > > > vblank_start = framedur_ns * crtc_vblank_start / crtc_vtotal > > > > > deadline = vblanktime + vblank_start > > > > > > > > > > That would be the expected time when the next start of vblank > > > > > happens. > > > > > > > > Except that drm_vblank_count_and_time() will give you the last > > > > sampled timestamp, which may be long ago in the past. Would > > > > need to add an _accurate version of that if we want to be > > > > guaranteed a fresh sample. > > > > > > IIRC the only time we wouldn't have a fresh sample is if the screen > > > has been idle for some time? > > > > IIRC "some time" == 1 idle frame, for any driver that sets > > vblank_disable_immediate. > > > > hmm, ok so it should be still good down to 30fps ;-) > > I thought we calculated based on frame # and line # on hw that > supported that? But it's been a while since looking at vblank code looks like drm_get_last_vbltimestamp() is what I want.. > BR, > -R > > > > In which case, I think that doesn't > > > matter. > > > > > > BR, > > > -R > > > > > > > > > > > -- > > > > Ville Syrjälä > > > > Intel > > > > -- > > Ville Syrjälä > > Intel
