Quoting Chris Wilson (2019-02-13 16:21:42) > Each set of registers we need to rewrite during a pageflip/modeset > increases the required evasion window. Modesets with PSR enabled > empirically take up to 350us to complete the register programming, so > provide a corresponding boost to the evasion window. > > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=105870 > Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> > Cc: Jani Nikula <jani.nikula@xxxxxxxxx> > Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> > Cc: Paulo Zanoni <paulo.r.zanoni@xxxxxxxxx> > Cc: Jose Roberto de Souza <jose.souza@xxxxxxxxx> > --- > drivers/gpu/drm/i915/intel_sprite.c | 20 ++++++++++++++++++-- > 1 file changed, 18 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/i915/intel_sprite.c b/drivers/gpu/drm/i915/intel_sprite.c > index 610398607e8e..03cafb953538 100644 > --- a/drivers/gpu/drm/i915/intel_sprite.c > +++ b/drivers/gpu/drm/i915/intel_sprite.c > @@ -84,14 +84,30 @@ void intel_pipe_update_start(const struct intel_crtc_state *new_crtc_state) > intel_crtc_has_type(new_crtc_state, INTEL_OUTPUT_DSI); > DEFINE_WAIT(wait); > u32 psr_status; > + int evasion; > > vblank_start = adjusted_mode->crtc_vblank_start; > if (adjusted_mode->flags & DRM_MODE_FLAG_INTERLACE) > vblank_start = DIV_ROUND_UP(vblank_start, 2); > > + /* > + * Estimate how long it will take to reprogram display registers. > + * > + * As we wish to avoid changing registers across the vblank to > + * avoid register write tearing, where the new frame uses an incomplete > + * mismash of state, we aim to complete our writes before the start > + * of the vblank. So we must delay starting our writes until after our > + * evasion window. > + * > + * Each additional bit of state adds a set of registers we need to > + * reprogram, increasing our required evasion window. > + */ > + evasion = VBLANK_EVASION_TIME_US; > + if (dev_priv->psr.enabled || new_crtc_state->has_psr) > + evasion += 300; > + > /* FIXME needs to be calibrated sensibly */ In terms of calibration, how about we couple the measured time back for use as evasion? Say use libavg so we adjust to different setups plus a safety factor, and reduce the error message to a warning/debug? -Chris _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
