On Tue, 17 Dec 2024, Mitul Golani <[email protected]> wrote: > Check if vblank is too short for scaler prefill latency. > > Signed-off-by: Mitul Golani <[email protected]> > --- > drivers/gpu/drm/i915/display/skl_watermark.c | 22 ++++++++++++++++++++ > 1 file changed, 22 insertions(+) > > diff --git a/drivers/gpu/drm/i915/display/skl_watermark.c > b/drivers/gpu/drm/i915/display/skl_watermark.c > index d3506e8ccd9b..a538e2b82c12 100644 > --- a/drivers/gpu/drm/i915/display/skl_watermark.c > +++ b/drivers/gpu/drm/i915/display/skl_watermark.c > @@ -2292,6 +2292,27 @@ static int icl_build_plane_wm(struct intel_crtc_state > *crtc_state, > return 0; > } > > +static int > +scaler_prefill_time(const struct intel_crtc_state *crtc_state) > +{ > + const struct intel_crtc_scaler_state *scaler_state = > + &crtc_state->scaler_state; > + int scaler_users = scaler_state->scaler_users; > + int count = 0; > + int hscale = scaler_state->scalers[0].hscale; > + int vscale = scaler_state->scalers[0].vscale; > + > + while (scaler_users) { > + count += scaler_users & 1; > + scaler_users >>= 1; > + }
See the hweight* family of functions for counting bits. BR, Jani. > + > + if (count > 1) > + return (4 * crtc_state->linetime * hscale * vscale); > + else > + return (4 * crtc_state->linetime); > +} > + > static bool > skl_is_vblank_too_short(const struct intel_crtc_state *crtc_state, > int wm0_lines, int latency) > @@ -2302,6 +2323,7 @@ skl_is_vblank_too_short(const struct intel_crtc_state > *crtc_state, > /* FIXME missing scaler and DSC pre-fill time */ > return crtc_state->framestart_delay + > intel_usecs_to_scanlines(adjusted_mode, latency) + > + scaler_prefill_time(crtc_state) + > wm0_lines > > adjusted_mode->crtc_vtotal - adjusted_mode->crtc_vblank_start; > } -- Jani Nikula, Intel
