linux-kernel - [PATCH 5.15 057/135] drm/msm/dp: dp_link_parse_sink_count() return immediately if aux read failed

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Message-Id: <20220627111939.812819579@linuxfoundation.org>
Date:   Mon, 27 Jun 2022 13:21:04 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Kuogee Hsieh <quic_khsieh@...cinc.com>,
        Stephen Boyd <swboyd@...omium.org>,
        Rob Clark <robdclark@...omium.org>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.15 057/135] drm/msm/dp: dp_link_parse_sink_count() return immediately if aux read failed

From: Kuogee Hsieh <quic_khsieh@...cinc.com>

[ Upstream commit f61550b3864b9578527c28cf9c465316ac1566e1 ]

Add checking aux read/write status at both dp_link_parse_sink_count()
and dp_link_parse_sink_status_filed() to avoid long timeout delay if
dp aux read/write failed at timeout due to cable unplugged.

Changes in V4:
-- split this patch as stand alone patch

Changes in v5:
-- rebase on msm-next branch

Signed-off-by: Kuogee Hsieh <quic_khsieh@...cinc.com>

Reviewed-by: Stephen Boyd <swboyd@...omium.org>
Tested-by: Stephen Boyd <swboyd@...omium.org>
Link: https://lore.kernel.org/r/1638985262-2072-1-git-send-email-quic_khsieh@quicinc.com
Signed-off-by: Rob Clark <robdclark@...omium.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/gpu/drm/msm/dp/dp_display.c | 12 +++++++++---
 drivers/gpu/drm/msm/dp/dp_link.c    | 19 ++++++++++++++-----
 2 files changed, 23 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
index a66ee63253a3..32b8dbb917bf 100644
--- a/drivers/gpu/drm/msm/dp/dp_display.c
+++ b/drivers/gpu/drm/msm/dp/dp_display.c
@@ -712,9 +712,15 @@ static int dp_irq_hpd_handle(struct dp_display_private *dp, u32 data)
 		return 0;
 	}
 
-	ret = dp_display_usbpd_attention_cb(&dp->pdev->dev);
-	if (ret == -ECONNRESET) { /* cable unplugged */
-		dp->core_initialized = false;
+	/*
+	 * dp core (ahb/aux clks) must be initialized before
+	 * irq_hpd be handled
+	 */
+	if (dp->core_initialized) {
+		ret = dp_display_usbpd_attention_cb(&dp->pdev->dev);
+		if (ret == -ECONNRESET) { /* cable unplugged */
+			dp->core_initialized = false;
+		}
 	}
 	DRM_DEBUG_DP("hpd_state=%d\n", state);
 
diff --git a/drivers/gpu/drm/msm/dp/dp_link.c b/drivers/gpu/drm/msm/dp/dp_link.c
index a5bdfc5029de..d4d31e5bda07 100644
--- a/drivers/gpu/drm/msm/dp/dp_link.c
+++ b/drivers/gpu/drm/msm/dp/dp_link.c
@@ -737,18 +737,25 @@ static int dp_link_parse_sink_count(struct dp_link *dp_link)
 	return 0;
 }
 
-static void dp_link_parse_sink_status_field(struct dp_link_private *link)
+static int dp_link_parse_sink_status_field(struct dp_link_private *link)
 {
 	int len = 0;
 
 	link->prev_sink_count = link->dp_link.sink_count;
-	dp_link_parse_sink_count(&link->dp_link);
+	len = dp_link_parse_sink_count(&link->dp_link);
+	if (len < 0) {
+		DRM_ERROR("DP parse sink count failed\n");
+		return len;
+	}
 
 	len = drm_dp_dpcd_read_link_status(link->aux,
 		link->link_status);
-	if (len < DP_LINK_STATUS_SIZE)
+	if (len < DP_LINK_STATUS_SIZE) {
 		DRM_ERROR("DP link status read failed\n");
-	dp_link_parse_request(link);
+		return len;
+	}
+
+	return dp_link_parse_request(link);
 }
 
 /**
@@ -1023,7 +1030,9 @@ int dp_link_process_request(struct dp_link *dp_link)
 
 	dp_link_reset_data(link);
 
-	dp_link_parse_sink_status_field(link);
+	ret = dp_link_parse_sink_status_field(link);
+	if (ret)
+		return ret;
 
 	if (link->request.test_requested == DP_TEST_LINK_EDID_READ) {
 		dp_link->sink_request |= DP_TEST_LINK_EDID_READ;
-- 
2.35.1