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 <ch...@chris-wilson.co.uk> Cc: Jani Nikula <jani.nik...@intel.com> Cc: Ville Syrjälä <ville.syrj...@linux.intel.com> Cc: Paulo Zanoni <paulo.r.zan...@intel.com> Cc: Jose Roberto de Souza <jose.so...@intel.com> --- 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 */ - min = vblank_start - intel_usecs_to_scanlines(adjusted_mode, - VBLANK_EVASION_TIME_US); + min = vblank_start - intel_usecs_to_scanlines(adjusted_mode, evasion); max = vblank_start - 1; if (min <= 0 || max <= 0) -- 2.20.1 _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx
