[Intel-gfx] [PATCH 4/6] drm/i915/xelpd: Handle PSR2 SDP indication in the prior scanline

[José Roberto de Souza]

In some modes there is not enough time during hblank to transmit PSR2
SDP plus the pixels CRC SDP, if such case happens PSR2 needs to be
disabled.
But eDP spec 1.4b allows to transmit PSR2 SDP in a prior scanline
alone and than later the CRC SDP, allowing PSR2 to be enabled in
those hblank constrained modes.

BSpec: 49274
Cc: Gwan-gyeong Mun <gwan-gyeong.mun at intel.com>
Signed-off-by: José Roberto de Souza <jose.souza at intel.com>
---
 .../drm/i915/display/intel_display_types.h    |  2 +
 drivers/gpu/drm/i915/display/intel_psr.c      | 37 +++++++++++++++++++
 drivers/gpu/drm/i915/i915_reg.h               |  1 +
 3 files changed, 40 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
index f89152ca52a20..56c4cb45c99df 100644
--- a/drivers/gpu/drm/i915/display/intel_display_types.h
+++ b/drivers/gpu/drm/i915/display/intel_display_types.h
@@ -1040,6 +1040,7 @@ struct intel_crtc_state {
 	bool has_psr;
 	bool has_psr2;
 	bool enable_psr2_sel_fetch;
+	bool req_psr2_sdp_prior_scanline;
 	u32 dc3co_exitline;
 	u16 su_y_granularity;
 
@@ -1494,6 +1495,7 @@ struct intel_psr {
 	bool colorimetry_support;
 	bool psr2_enabled;
 	bool psr2_sel_fetch_enabled;
+	bool req_psr2_sdp_prior_scanline;
 	u8 sink_sync_latency;
 	ktime_t last_entry_attempt;
 	ktime_t last_exit;
diff --git a/drivers/gpu/drm/i915/display/intel_psr.c b/drivers/gpu/drm/i915/display/intel_psr.c
index e508816911fad..3cb8758be4042 100644
--- a/drivers/gpu/drm/i915/display/intel_psr.c
+++ b/drivers/gpu/drm/i915/display/intel_psr.c
@@ -418,6 +418,9 @@ static void intel_psr_enable_sink(struct intel_dp *intel_dp)
 			dpcd_val |= DP_PSR_CRC_VERIFICATION;
 	}
 
+	if (intel_dp->psr.req_psr2_sdp_prior_scanline)
+		dpcd_val |= DP_PSR_SU_REGION_SCANLINE_CAPTURE;
+
 	drm_dp_dpcd_writeb(&intel_dp->aux, DP_PSR_EN_CFG, dpcd_val);
 
 	drm_dp_dpcd_writeb(&intel_dp->aux, DP_SET_POWER, DP_SET_POWER_D0);
@@ -585,6 +588,9 @@ static void hsw_activate_psr2(struct intel_dp *intel_dp)
 		val |= EDP_PSR2_FAST_WAKE(7);
 	}
 
+	if (intel_dp->psr.req_psr2_sdp_prior_scanline)
+		val |= EDP_PSR2_SU_SDP_SCANLINE;
+
 	if (intel_dp->psr.psr2_sel_fetch_enabled) {
 		/* WA 1408330847 */
 		if (IS_TGL_DISPLAY_STEP(dev_priv, STEP_A0, STEP_A0) ||
@@ -814,6 +820,29 @@ static bool psr2_granularity_check(struct intel_dp *intel_dp,
 	return true;
 }
 
+static bool _compute_psr2_sdp_prior_scanline_indication(struct intel_dp *intel_dp,
+							struct intel_crtc_state *crtc_state)
+{
+	const struct drm_display_mode *adjusted_mode = &crtc_state->uapi.adjusted_mode;
+	struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
+	u32 hblank_total, hblank_ns, req_ns;
+
+	hblank_total = adjusted_mode->crtc_hblank_end - adjusted_mode->crtc_hblank_start;
+	hblank_ns = div_u64(1000000ULL * hblank_total, adjusted_mode->crtc_clock);
+
+	/* From spec: (72 / number of lanes) * 1000 / symbol clock frequency MHz */
+	req_ns = (72 / crtc_state->lane_count) * 1000 / (crtc_state->port_clock / 1000);
+
+	if ((hblank_ns - req_ns) > 100)
+		return true;
+
+	if (DISPLAY_VER(dev_priv) < 13 || intel_dp->edp_dpcd[0] < DP_EDP_14b)
+		return false;
+
+	crtc_state->req_psr2_sdp_prior_scanline = true;
+	return true;
+}
+
 static bool intel_psr2_config_valid(struct intel_dp *intel_dp,
 				    struct intel_crtc_state *crtc_state)
 {
@@ -926,6 +955,12 @@ static bool intel_psr2_config_valid(struct intel_dp *intel_dp,
 		return false;
 	}
 
+	if (!_compute_psr2_sdp_prior_scanline_indication(intel_dp, crtc_state)) {
+		drm_dbg_kms(&dev_priv->drm,
+			    "PSR2 not enabled, PSR2 SDP indication do not fit in hblank\n");
+		return false;
+	}
+
 	tgl_dc3co_exitline_compute_config(intel_dp, crtc_state);
 	return true;
 }
@@ -1173,6 +1208,8 @@ static void intel_psr_enable_locked(struct intel_dp *intel_dp,
 	intel_dp->psr.dc3co_exit_delay = val;
 	intel_dp->psr.dc3co_exitline = crtc_state->dc3co_exitline;
 	intel_dp->psr.psr2_sel_fetch_enabled = crtc_state->enable_psr2_sel_fetch;
+	intel_dp->psr.req_psr2_sdp_prior_scanline =
+		crtc_state->req_psr2_sdp_prior_scanline;
 
 	if (!psr_interrupt_error_check(intel_dp))
 		return;
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 568e5f108e2c4..e0bd60fe7a190 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -4590,6 +4590,7 @@ enum {
 #define   TGL_EDP_PSR2_BLOCK_COUNT_NUM_2	(0 << 28)
 #define   TGL_EDP_PSR2_BLOCK_COUNT_NUM_3	(1 << 28)
 #define   EDP_Y_COORDINATE_ENABLE		REG_BIT(25) /* display 10, 11 and 12 */
+#define   EDP_PSR2_SU_SDP_SCANLINE		REG_BIT(25) /* display 13+ */
 #define   EDP_MAX_SU_DISABLE_TIME(t)		((t) << 20)
 #define   EDP_MAX_SU_DISABLE_TIME_MASK		(0x1f << 20)
 #define   EDP_PSR2_IO_BUFFER_WAKE_MAX_LINES	8
-- 
2.32.0