From: Jouni Högander <jouni.hogander@intel.com>
Date: Tue, 30 Jan 2024 11:11:29 +0000 (+0200)
Subject: drm/i915/alpm: Calculate ALPM Entry check
X-Git-Url: https://repo.jachan.dev/J-linux.git/commitdiff_plain/29f3067a236ac55f245ea8f23712a0d240cf1f30

drm/i915/alpm: Calculate ALPM Entry check

ALPM Entry Check represents the number of lines needed to put the main link
to sleep and keep it in the sleep state before it can be taken out of the
SLEEP state (eDP requires the main link to be in the SLEEP state for a
minimum of 5us).

Bspec: 71477

v2: move display version check into _lnl_compute_alpm_param

Signed-off-by: Jouni Högander <jouni.hogander@intel.com>
Reviewed-by: Arun R Murthy <arun.r.murthy@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240130111130.3298779-4-jouni.hogander@intel.com
---

diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
index ce75b7d55a8a..01eb6e4e6049 100644
--- a/drivers/gpu/drm/i915/display/intel_display_types.h
+++ b/drivers/gpu/drm/i915/display/intel_display_types.h
@@ -1716,6 +1716,9 @@ struct intel_psr {
 	struct {
 		u8 io_wake_lines;
 		u8 fast_wake_lines;
+
+		/* LNL and beyond */
+		u8 check_entry_lines;
 	} alpm_parameters;
 
 	ktime_t last_entry_attempt;
diff --git a/drivers/gpu/drm/i915/display/intel_psr.c b/drivers/gpu/drm/i915/display/intel_psr.c
index 4bca1107997f..7aedda0ca2d2 100644
--- a/drivers/gpu/drm/i915/display/intel_psr.c
+++ b/drivers/gpu/drm/i915/display/intel_psr.c
@@ -1126,6 +1126,30 @@ static bool _compute_psr2_sdp_prior_scanline_indication(struct intel_dp *intel_d
 	return true;
 }
 
+static bool _lnl_compute_alpm_params(struct intel_dp *intel_dp,
+				     struct intel_crtc_state *crtc_state)
+{
+	struct drm_i915_private *i915 = dp_to_i915(intel_dp);
+	int check_entry_lines;
+
+	if (DISPLAY_VER(i915) < 20)
+		return true;
+
+	/* ALPM Entry Check = 2 + CEILING( 5us /tline ) */
+	check_entry_lines = 2 +
+		intel_usecs_to_scanlines(&crtc_state->hw.adjusted_mode, 5);
+
+	if (check_entry_lines > 15)
+		return false;
+
+	if (i915->display.params.psr_safest_params)
+		check_entry_lines = 15;
+
+	intel_dp->psr.alpm_parameters.check_entry_lines = check_entry_lines;
+
+	return true;
+}
+
 static bool _compute_alpm_params(struct intel_dp *intel_dp,
 				 struct intel_crtc_state *crtc_state)
 {
@@ -1140,6 +1164,8 @@ static bool _compute_alpm_params(struct intel_dp *intel_dp,
 		 * it is not enough -> use 45 us.
 		 */
 		fast_wake_time = 45;
+
+		/* TODO: Check how we can use ALPM_CTL fast wake extended field */
 		max_wake_lines = 12;
 	} else {
 		io_wake_time = 50;
@@ -1156,6 +1182,9 @@ static bool _compute_alpm_params(struct intel_dp *intel_dp,
 	    fast_wake_lines > max_wake_lines)
 		return false;
 
+	if (!_lnl_compute_alpm_params(intel_dp, crtc_state))
+		return false;
+
 	if (i915->display.params.psr_safest_params)
 		io_wake_lines = fast_wake_lines = max_wake_lines;