linux-kernel - [PATCH] drm/msm/dp: postpone irq_hpd event during connection pending state

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Message-Id: <1608314020-26791-1-git-send-email-khsieh@codeaurora.org>
Date:   Fri, 18 Dec 2020 09:53:40 -0800
From:   Kuogee Hsieh <khsieh@...eaurora.org>
To:     robdclark@...il.com, sean@...rly.run, swboyd@...omium.org
Cc:     tanmay@...eaurora.org, abhinavk@...eaurora.org,
        aravindh@...eaurora.org, khsieh@...eaurora.org,
        rnayak@...eaurora.org, airlied@...ux.ie, daniel@...ll.ch,
        linux-arm-msm@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        freedreno@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Subject: [PATCH] drm/msm/dp: postpone irq_hpd event during connection pending state

irq_hpd event can only be executed at connected state. Therefore
irq_hpd event should be postponed if it happened at connection
pending state. This patch also make sure both link rate and lane
are valid before start link training.

Signed-off-by: Kuogee Hsieh <khsieh@...eaurora.org>
---
 drivers/gpu/drm/msm/dp/dp_display.c |  7 +++++++
 drivers/gpu/drm/msm/dp/dp_panel.c   | 12 +++++++++---
 2 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
index 6e971d5..3bc7ed2 100644
--- a/drivers/gpu/drm/msm/dp/dp_display.c
+++ b/drivers/gpu/drm/msm/dp/dp_display.c
@@ -693,6 +693,13 @@ static int dp_irq_hpd_handle(struct dp_display_private *dp, u32 data)
 		return 0;
 	}
 
+	if (state == ST_CONNECT_PENDING) {
+		/* wait until ST_CONNECTED */
+		dp_add_event(dp, EV_IRQ_HPD_INT, 0, 1); /* delay = 1 */
+		mutex_unlock(&dp->event_mutex);
+		return 0;
+	}
+
 	ret = dp_display_usbpd_attention_cb(&dp->pdev->dev);
 	if (ret == -ECONNRESET) { /* cable unplugged */
 		dp->core_initialized = false;
diff --git a/drivers/gpu/drm/msm/dp/dp_panel.c b/drivers/gpu/drm/msm/dp/dp_panel.c
index 97dca3e..d1780bc 100644
--- a/drivers/gpu/drm/msm/dp/dp_panel.c
+++ b/drivers/gpu/drm/msm/dp/dp_panel.c
@@ -167,12 +167,18 @@ int dp_panel_read_sink_caps(struct dp_panel *dp_panel,
 	panel = container_of(dp_panel, struct dp_panel_private, dp_panel);
 
 	rc = dp_panel_read_dpcd(dp_panel);
+	if (rc) {
+		DRM_ERROR("read dpcd failed %d\n", rc);
+		return rc;
+	}
+
 	bw_code = drm_dp_link_rate_to_bw_code(dp_panel->link_info.rate);
-	if (rc || !is_link_rate_valid(bw_code) ||
+	if (!is_link_rate_valid(bw_code) ||
 			!is_lane_count_valid(dp_panel->link_info.num_lanes) ||
 			(bw_code > dp_panel->max_bw_code)) {
-		DRM_ERROR("read dpcd failed %d\n", rc);
-		return rc;
+		DRM_ERROR("Illegal link rate=%d lane=%d\n", dp_panel->link_info.rate,
+				dp_panel->link_info.num_lanes);
+		return -EINVAL;
 	}
 
 	if (dp_panel->dfp_present) {
-- 
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