Currently, crtc_vblank_start is read from either the VBLANK_START register (on pre-ADL platforms) or computed as vdisplay + set_context_latency in intel_get_transcoder_timings().
This works when the entire vblank region after vdisplay is treated as guardband, i.e.: delayed vblank start = vdisplay + SCL = vtotal - guardband. However, with optimized guardband, the guardband becomes shorter, and the delayed vblank_start moves further away from vdisplay. For platforms where intel_vrr_always_use_vrr_tg == false, the delayed vblank start is only relevant in VRR mode. We retain the original crtc_vblank_start and apply adjustments in VRR-specific paths. Evasion logic, push clear already use vtotal - guardband directly for VRR case. On platforms where intel_vrr_always_use_vrr_tg == true, the delayed vblank_start is used in both fixed and VRR modes. So we need to change the crtc_vblank_start so that fixed rr case works properly. Therefore for the readout, we need to overwrite crtc_vblank_start with vtotal - guardband to ensure correct behavior across both modes. This change prepares the pipeline for optimized guardband usage by ensuring crtc_vblank_start reflects the correct timing on platforms with always-on VRR TG. Signed-off-by: Ankit Nautiyal <[email protected]> --- drivers/gpu/drm/i915/display/intel_vrr.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/drivers/gpu/drm/i915/display/intel_vrr.c b/drivers/gpu/drm/i915/display/intel_vrr.c index 8d71d7dc9d12..221b25832e56 100644 --- a/drivers/gpu/drm/i915/display/intel_vrr.c +++ b/drivers/gpu/drm/i915/display/intel_vrr.c @@ -821,6 +821,20 @@ void intel_vrr_get_config(struct intel_crtc_state *crtc_state) */ if (crtc_state->vrr.enable) crtc_state->mode_flags |= I915_MODE_FLAG_VRR; + + /* + * For platforms that always use the VRR timing generator, we overwrite + * crtc_vblank_start with vtotal - guardband to reflect the delayed + * vblank start. This works for both default and optimized guardband values. + * On other platforms, we keep the original value from + * intel_get_transcoder_timings() and apply adjustments only in VRR-specific + * paths as needed. + */ + if (intel_vrr_always_use_vrr_tg(display)) + crtc_state->hw.adjusted_mode.crtc_vblank_start = + crtc_state->hw.adjusted_mode.crtc_vtotal - + crtc_state->vrr.guardband; + } int intel_vrr_safe_window_start(const struct intel_crtc_state *crtc_state) -- 2.45.2
