On Mon, 06 Mar 2023, Ville Syrjala <ville.syrjala@xxxxxxxxxxxxxxx> wrote:
> From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
>
> Pull the scanline_offset calculation into its own function. Might
> have further use for this later with DSB scanline waits.
>
> Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
Reviewed-by: Jani Nikula <jani.nikula@xxxxxxxxx>
> ---
> drivers/gpu/drm/i915/display/intel_vblank.c | 89 +++++++++++----------
> 1 file changed, 48 insertions(+), 41 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_vblank.c b/drivers/gpu/drm/i915/display/intel_vblank.c
> index 48bf3923af11..f8bf9810527d 100644
> --- a/drivers/gpu/drm/i915/display/intel_vblank.c
> +++ b/drivers/gpu/drm/i915/display/intel_vblank.c
> @@ -441,6 +441,53 @@ void intel_wait_for_pipe_scanline_moving(struct intel_crtc *crtc)
> wait_for_pipe_scanline_moving(crtc, true);
> }
>
> +static int intel_crtc_scanline_offset(const struct intel_crtc_state *crtc_state)
> +{
> + struct drm_i915_private *i915 = to_i915(crtc_state->uapi.crtc->dev);
> + const struct drm_display_mode *adjusted_mode = &crtc_state->hw.adjusted_mode;
> +
> + /*
> + * The scanline counter increments at the leading edge of hsync.
> + *
> + * On most platforms it starts counting from vtotal-1 on the
> + * first active line. That means the scanline counter value is
> + * always one less than what we would expect. Ie. just after
> + * start of vblank, which also occurs at start of hsync (on the
> + * last active line), the scanline counter will read vblank_start-1.
> + *
> + * On gen2 the scanline counter starts counting from 1 instead
> + * of vtotal-1, so we have to subtract one (or rather add vtotal-1
> + * to keep the value positive), instead of adding one.
> + *
> + * On HSW+ the behaviour of the scanline counter depends on the output
> + * type. For DP ports it behaves like most other platforms, but on HDMI
> + * there's an extra 1 line difference. So we need to add two instead of
> + * one to the value.
> + *
> + * On VLV/CHV DSI the scanline counter would appear to increment
> + * approx. 1/3 of a scanline before start of vblank. Unfortunately
> + * that means we can't tell whether we're in vblank or not while
> + * we're on that particular line. We must still set scanline_offset
> + * to 1 so that the vblank timestamps come out correct when we query
> + * the scanline counter from within the vblank interrupt handler.
> + * However if queried just before the start of vblank we'll get an
> + * answer that's slightly in the future.
> + */
> + if (DISPLAY_VER(i915) == 2) {
> + int vtotal;
> +
> + vtotal = adjusted_mode->crtc_vtotal;
> + if (adjusted_mode->flags & DRM_MODE_FLAG_INTERLACE)
> + vtotal /= 2;
> +
> + return vtotal - 1;
> + } else if (HAS_DDI(i915) && intel_crtc_has_type(crtc_state, INTEL_OUTPUT_HDMI)) {
> + return 2;
> + } else {
> + return 1;
> + }
> +}
> +
> void intel_crtc_update_active_timings(const struct intel_crtc_state *crtc_state)
> {
> struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
> @@ -479,47 +526,7 @@ void intel_crtc_update_active_timings(const struct intel_crtc_state *crtc_state)
>
> crtc->mode_flags = crtc_state->mode_flags;
>
> - /*
> - * The scanline counter increments at the leading edge of hsync.
> - *
> - * On most platforms it starts counting from vtotal-1 on the
> - * first active line. That means the scanline counter value is
> - * always one less than what we would expect. Ie. just after
> - * start of vblank, which also occurs at start of hsync (on the
> - * last active line), the scanline counter will read vblank_start-1.
> - *
> - * On gen2 the scanline counter starts counting from 1 instead
> - * of vtotal-1, so we have to subtract one (or rather add vtotal-1
> - * to keep the value positive), instead of adding one.
> - *
> - * On HSW+ the behaviour of the scanline counter depends on the output
> - * type. For DP ports it behaves like most other platforms, but on HDMI
> - * there's an extra 1 line difference. So we need to add two instead of
> - * one to the value.
> - *
> - * On VLV/CHV DSI the scanline counter would appear to increment
> - * approx. 1/3 of a scanline before start of vblank. Unfortunately
> - * that means we can't tell whether we're in vblank or not while
> - * we're on that particular line. We must still set scanline_offset
> - * to 1 so that the vblank timestamps come out correct when we query
> - * the scanline counter from within the vblank interrupt handler.
> - * However if queried just before the start of vblank we'll get an
> - * answer that's slightly in the future.
> - */
> - if (DISPLAY_VER(i915) == 2) {
> - int vtotal;
> -
> - vtotal = adjusted_mode.crtc_vtotal;
> - if (adjusted_mode.flags & DRM_MODE_FLAG_INTERLACE)
> - vtotal /= 2;
> -
> - crtc->scanline_offset = vtotal - 1;
> - } else if (HAS_DDI(i915) &&
> - intel_crtc_has_type(crtc_state, INTEL_OUTPUT_HDMI)) {
> - crtc->scanline_offset = 2;
> - } else {
> - crtc->scanline_offset = 1;
> - }
> + crtc->scanline_offset = intel_crtc_scanline_offset(crtc_state);
>
> spin_unlock(&i915->uncore.lock);
> spin_unlock_irqrestore(&i915->drm.vblank_time_lock, irqflags);
--
Jani Nikula, Intel Open Source Graphics Center
