linux-kernel - [PATCH] drm/i915/cx0: Set power state to ready only on owned PHY lanes

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Message-ID: <20240919182952.51326-1-vamsikrishna.brahmajosyula@gmail.com>
Date: Thu, 19 Sep 2024 23:59:52 +0530
From: Vamsi Krishna Brahmajosyula <vamsikrishna.brahmajosyula@...il.com>
To: gustavo.sousa@...el.com,
	jani.nikula@...ux.intel.com,
	rodrigo.vivi@...el.com,
	joonas.lahtinen@...ux.intel.com,
	tursulin@...ulin.net,
	airlied@...il.com,
	daniel@...ll.ch
Cc: skhan@...uxfoundation.org,
	intel-gfx@...ts.freedesktop.org,
	intel-xe@...ts.freedesktop.org,
	dri-devel@...ts.freedesktop.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH] drm/i915/cx0: Set power state to ready only on owned PHY lanes

In DP alt mode, when pin assignment is D, only one PHY lane is owned
by the display. intel_cx0pll_enable currently performs a power state
ready on both the lanes in all cases.

Address the todo to perfom power state ready on owned lanes.

Tested on Meteor Lake-P [Intel Arc Graphics] with DP alt mode.

v2 -> v3:
- Fix changelog per Jani Nikula's feedback
v1 -> v2: Address Gustavo Sousa's feedback
- Use owned lanes mask to set Phy power state to Ready, instead of
  maxpclk_lane with DP alt mode check.
- Owned lanes are obtained from intel_cx0_get_owned_lane_mask().

Signed-off-by: Vamsi Krishna Brahmajosyula <vamsikrishna.brahmajosyula@...il.com>
---
Patch version removed so that patchwork would recognize the entry

 drivers/gpu/drm/i915/display/intel_cx0_phy.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_cx0_phy.c b/drivers/gpu/drm/i915/display/intel_cx0_phy.c
index 4a6c3040ca15..cbed53d3b250 100644
--- a/drivers/gpu/drm/i915/display/intel_cx0_phy.c
+++ b/drivers/gpu/drm/i915/display/intel_cx0_phy.c
@@ -2934,6 +2934,7 @@ static void intel_cx0pll_enable(struct intel_encoder *encoder,
 	enum phy phy = intel_encoder_to_phy(encoder);
 	struct intel_digital_port *dig_port = enc_to_dig_port(encoder);
 	bool lane_reversal = dig_port->saved_port_bits & DDI_BUF_PORT_REVERSAL;
+	u8 owned_lane_mask = intel_cx0_get_owned_lane_mask(encoder);
 	u8 maxpclk_lane = lane_reversal ? INTEL_CX0_LANE1 :
 					  INTEL_CX0_LANE0;
 	intel_wakeref_t wakeref = intel_cx0_phy_transaction_begin(encoder);
@@ -2948,10 +2949,9 @@ static void intel_cx0pll_enable(struct intel_encoder *encoder,
 	intel_cx0_phy_lane_reset(encoder, lane_reversal);
 
 	/*
-	 * 3. Change Phy power state to Ready.
-	 * TODO: For DP alt mode use only one lane.
+	 * 3. Change Phy power state to Ready on owned lanes.
 	 */
-	intel_cx0_powerdown_change_sequence(encoder, INTEL_CX0_BOTH_LANES,
+	intel_cx0_powerdown_change_sequence(encoder, owned_lane_mask,
 					    CX0_P2_STATE_READY);
 
 	/*

base-commit: ad060dbbcfcfcba624ef1a75e1d71365a98b86d8
-- 
2.46.0