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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Philipp Zabel <p.zabel@pengutronix.de>,
        Andrey Gusakov <andrey.gusakov@cogentembedded.com>,
        Andrzej Hajda <a.hajda@samsung.com>,
        Sasha Levin <alexander.levin@microsoft.com>
Subject: [PATCH 4.9 59/86] drm/bridge: tc358767: fix 1-lane behavior
Date:   Fri,  2 Feb 2018 17:58:19 +0100
Message-Id: <20180202140827.987254394@linuxfoundation.org>
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4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Andrey Gusakov <andrey.gusakov@cogentembedded.com>


[ Upstream commit 4dbd6c03fbf88299c573d676838896c6e06aade2 ]

Use drm_dp_channel_eq_ok helper

Acked-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Andrey Gusakov <andrey.gusakov@cogentembedded.com>
Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1510073785-16108-7-git-send-email-andrey.gusakov@cogentembedded.com
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/gpu/drm/bridge/tc358767.c |   13 +++----------
 1 file changed, 3 insertions(+), 10 deletions(-)

--- a/drivers/gpu/drm/bridge/tc358767.c
+++ b/drivers/gpu/drm/bridge/tc358767.c
@@ -819,8 +819,6 @@ static int tc_main_link_setup(struct tc_
 	unsigned int rate;
 	u32 dp_phy_ctrl;
 	int timeout;
-	bool aligned;
-	bool ready;
 	u32 value;
 	int ret;
 	u8 tmp[8];
@@ -965,16 +963,15 @@ static int tc_main_link_setup(struct tc_
 		ret = drm_dp_dpcd_read_link_status(aux, tmp + 2);
 		if (ret < 0)
 			goto err_dpcd_read;
-		ready = (tmp[2] == ((DP_CHANNEL_EQ_BITS << 4) | /* Lane1 */
-				     DP_CHANNEL_EQ_BITS));      /* Lane0 */
-		aligned = tmp[4] & DP_INTERLANE_ALIGN_DONE;
-	} while ((--timeout) && !(ready && aligned));
+	} while ((--timeout) &&
+		 !(drm_dp_channel_eq_ok(tmp + 2,  tc->link.base.num_lanes)));
 
 	if (timeout == 0) {
 		/* Read DPCD 0x200-0x201 */
 		ret = drm_dp_dpcd_read(aux, DP_SINK_COUNT, tmp, 2);
 		if (ret < 0)
 			goto err_dpcd_read;
+		dev_err(dev, "channel(s) EQ not ok\n");
 		dev_info(dev, "0x0200 SINK_COUNT: 0x%02x\n", tmp[0]);
 		dev_info(dev, "0x0201 DEVICE_SERVICE_IRQ_VECTOR: 0x%02x\n",
 			 tmp[1]);
@@ -985,10 +982,6 @@ static int tc_main_link_setup(struct tc_
 		dev_info(dev, "0x0206 ADJUST_REQUEST_LANE0_1: 0x%02x\n",
 			 tmp[6]);
 
-		if (!ready)
-			dev_err(dev, "Lane0/1 not ready\n");
-		if (!aligned)
-			dev_err(dev, "Lane0/1 not aligned\n");
 		return -EAGAIN;
 	}