Commit b5202a93 authored by Ville Syrjälä's avatar Ville Syrjälä
Browse files

drm/i915: Extract intel_crtc_scanline_offset() 



Pull the scanline_offset calculation into its own function. Might
have further use for this later with DSB scanline waits.

Reviewed-by: default avatarJani Nikula <jani.nikula@intel.com>
Reviewed-by: default avatarMitul Golani <mitulkumar.ajitkumar.golani@intel.com>
Signed-off-by: default avatarVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230310235828.17439-4-ville.syrjala@linux.intel.com
parent 84f4ebe8

drivers/gpu/drm/i915/display/intel_vblank.c

+48 −41
Original line number Diff line number Diff line
@@ -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);