On Thu, Oct 09, 2025 at 02:30:57PM +0530, Ankit Nautiyal wrote: > Currently crtc_vblank_start is assumed to be the vblank_start for the fixed > refresh rate case. That value can be different from the variable refresh > rate case whenever always_use_vrr_tg()==false. On icl/tgl it's always > different due to the extra vblank delay, and also on adl+ it could be > different if we were to use an optimized guardband. > > So places where crtc_vblank_start is used to compute vblank length needs > change so as to account for cases where vrr is enabled. Specifically > with vrr.enable the effective vblank length is actually guardband. > > Add a helper to get the correct vblank length for both vrr and fixed > refresh rate cases. Use this helper where vblank_start is used to > compute the vblank length. > > Signed-off-by: Ankit Nautiyal <[email protected]>
Reviewed-by: Ville Syrjälä <[email protected]> > --- > drivers/gpu/drm/i915/display/intel_vblank.c | 10 ++++++++++ > drivers/gpu/drm/i915/display/intel_vblank.h | 2 ++ > drivers/gpu/drm/i915/display/skl_watermark.c | 3 ++- > 3 files changed, 14 insertions(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/i915/display/intel_vblank.c > b/drivers/gpu/drm/i915/display/intel_vblank.c > index 0b7fcc05e64c..2fc0c1c0bb87 100644 > --- a/drivers/gpu/drm/i915/display/intel_vblank.c > +++ b/drivers/gpu/drm/i915/display/intel_vblank.c > @@ -767,3 +767,13 @@ int intel_vblank_evade(struct intel_vblank_evade_ctx > *evade) > > return scanline; > } > + > +int intel_crtc_vblank_length(const struct intel_crtc_state *crtc_state) > +{ > + const struct drm_display_mode *adjusted_mode = > &crtc_state->hw.adjusted_mode; > + > + if (crtc_state->vrr.enable) > + return crtc_state->vrr.guardband; > + else > + return adjusted_mode->crtc_vtotal - > adjusted_mode->crtc_vblank_start; > +} > diff --git a/drivers/gpu/drm/i915/display/intel_vblank.h > b/drivers/gpu/drm/i915/display/intel_vblank.h > index 21fbb08d61d5..98d04cacd65f 100644 > --- a/drivers/gpu/drm/i915/display/intel_vblank.h > +++ b/drivers/gpu/drm/i915/display/intel_vblank.h > @@ -48,4 +48,6 @@ const struct intel_crtc_state * > intel_pre_commit_crtc_state(struct intel_atomic_state *state, > struct intel_crtc *crtc); > > +int intel_crtc_vblank_length(const struct intel_crtc_state *crtc_state); > + > #endif /* __INTEL_VBLANK_H__ */ > diff --git a/drivers/gpu/drm/i915/display/skl_watermark.c > b/drivers/gpu/drm/i915/display/skl_watermark.c > index 9df9ee137bf9..06e5e6c77d2e 100644 > --- a/drivers/gpu/drm/i915/display/skl_watermark.c > +++ b/drivers/gpu/drm/i915/display/skl_watermark.c > @@ -28,6 +28,7 @@ > #include "intel_flipq.h" > #include "intel_pcode.h" > #include "intel_plane.h" > +#include "intel_vblank.h" > #include "intel_wm.h" > #include "skl_universal_plane_regs.h" > #include "skl_watermark.h" > @@ -2241,7 +2242,7 @@ skl_is_vblank_too_short(const struct intel_crtc_state > *crtc_state, > scaler_prefill_latency(crtc_state) + > dsc_prefill_latency(crtc_state) + > wm0_lines > > - adjusted_mode->crtc_vtotal - adjusted_mode->crtc_vblank_start; > + intel_crtc_vblank_length(crtc_state); > } > > static int skl_max_wm0_lines(const struct intel_crtc_state *crtc_state) > -- > 2.45.2 -- Ville Syrjälä Intel
