On Wed, Sep 24, 2025 at 07:45:42PM +0530, Ankit Nautiyal wrote:
> Drop the now single-use dsb_vblank_delay() helper and inline its logic
> directly into intel_dsb_wait_for_delayed_vblank().
>
> This will help to keep all VRR related wait stuff in one place.
>
> Signed-off-by: Ankit Nautiyal <[email protected]>
> ---
> drivers/gpu/drm/i915/display/intel_dsb.c | 56 ++++++++++--------------
> 1 file changed, 24 insertions(+), 32 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_dsb.c
> b/drivers/gpu/drm/i915/display/intel_dsb.c
> index ae8574880ef2..44a465ff52d4 100644
> --- a/drivers/gpu/drm/i915/display/intel_dsb.c
> +++ b/drivers/gpu/drm/i915/display/intel_dsb.c
> @@ -115,24 +115,6 @@ static bool pre_commit_is_vrr_active(struct
> intel_atomic_state *state,
> return old_crtc_state->vrr.enable && !intel_crtc_vrr_disabling(state,
> crtc);
> }
>
> -static int dsb_vblank_delay(struct intel_atomic_state *state,
> - struct intel_crtc *crtc)
> -{
> - const struct intel_crtc_state *crtc_state =
> - intel_pre_commit_crtc_state(state, crtc);
> -
> - if (pre_commit_is_vrr_active(state, crtc))
> - /*
> - * When the push is sent during vblank it will trigger
> - * on the next scanline, hence we have up to one extra
> - * scanline until the delayed vblank occurs after
> - * TRANS_PUSH has been written.
> - */
> - return crtc_state->set_context_latency + 1;
> - else
> - return intel_mode_vblank_delay(&crtc_state->hw.adjusted_mode);
> -}
> -
> static int dsb_vtotal(struct intel_atomic_state *state,
> struct intel_crtc *crtc)
> {
> @@ -821,24 +803,34 @@ void intel_dsb_wait_for_delayed_vblank(struct
> intel_atomic_state *state,
> struct intel_crtc *crtc = dsb->crtc;
> const struct intel_crtc_state *crtc_state =
> intel_pre_commit_crtc_state(state, crtc);
> - int usecs = intel_scanlines_to_usecs(&crtc_state->hw.adjusted_mode,
> - dsb_vblank_delay(state, crtc));
> + int usecs;
>
> - /*
> - * If the push happened before the vmin decision boundary
> - * we don't know how far we are from the undelayed vblank.
> - * Wait until we're past the vmin safe window, at which
> - * point we're SCL lines away from the delayed vblank.
> - *
> - * If the push happened after the vmin decision boundary
> - * the hardware itself guarantees that we're SCL lines
> - * away from the delayed vblank, and we won't be inside
> - * the vmin safe window so this extra wait does nothing.
> - */
> - if (pre_commit_is_vrr_active(state, crtc))
> + if (pre_commit_is_vrr_active(state, crtc)) {
> + /*
> + * If the push happened before the vmin decision boundary
> + * we don't know how far we are from the undelayed vblank.
> + * Wait until we're past the vmin safe window, at which
> + * point we're SCL lines away from the delayed vblank.
> + *
> + * If the push happened after the vmin decision boundary
> + * the hardware itself guarantees that we're SCL lines
> + * away from the delayed vblank, and we won't be inside
> + * the vmin safe window so this extra wait does nothing.
> + */
> intel_dsb_wait_scanline_out(state, dsb,
>
> intel_vrr_safe_window_start(crtc_state),
>
> intel_vrr_vmin_safe_window_end(crtc_state));
> + /*
> + * When the push is sent during vblank it will trigger
> + * on the next scanline, hence we have up to one extra
> + * scanline until the delayed vblank occurs after
> + * TRANS_PUSH has been written.
> + */
> + usecs = intel_scanlines_to_usecs(&crtc_state->hw.adjusted_mode,
> +
> crtc_state->set_context_latency + 1);
> + } else {
> + usecs = intel_mode_vblank_delay(&crtc_state->hw.adjusted_mode);
That also returns the delay in scanlines.
> + }
>
> intel_dsb_wait_usec(dsb, usecs);
So I guess just do the scanline_to_usec() conversion here when calling
wait_usec().
I think eventually we may want to change this part to be:
if (something)
intel_dsb_wait_hblanks(x);
else
intel_dsb_wait_usec(intel_scanlines_to_usecs(x));
But need to figure out what that "something" is. IIRC bspec
might not actually say which platforms have the "wait hblanks"
command. I gave it quick try on LNL but it didn't seem to work
there.
--
Ville Syrjälä
Intel
