linux-kernel - [PATCH 4.19 026/113] drm/amd/display: extending AUX SW Timeout

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Message-Id: <20190515090655.490560298@linuxfoundation.org>
Date:   Wed, 15 May 2019 12:55:17 +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, Martin Leung <martin.leung@....com>,
        Jun Lei <Jun.Lei@....com>,
        Joshua Aberback <Joshua.Aberback@....com>,
        Leo Li <sunpeng.li@....com>,
        Alex Deucher <alexander.deucher@....com>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 4.19 026/113] drm/amd/display: extending AUX SW Timeout

[ Upstream commit f4bbebf8e7eb4d294b040ab2d2ba71e70e69b930 ]

[Why]
AUX takes longer to reply when using active DP-DVI dongle on some asics
resulting in up to 2000+ us edid read (timeout).

[How]
1. Adjust AUX poll to match spec
2. Extend the SW timeout. This does not affect normal
operation since we exit the loop as soon as AUX acks.

Signed-off-by: Martin Leung <martin.leung@....com>
Reviewed-by: Jun Lei <Jun.Lei@....com>
Acked-by: Joshua Aberback <Joshua.Aberback@....com>
Acked-by: Leo Li <sunpeng.li@....com>
Signed-off-by: Alex Deucher <alexander.deucher@....com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/gpu/drm/amd/display/dc/dce/dce_aux.c | 9 ++++++---
 drivers/gpu/drm/amd/display/dc/dce/dce_aux.h | 6 +++---
 2 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/dce/dce_aux.c b/drivers/gpu/drm/amd/display/dc/dce/dce_aux.c
index 3f5b2e6f7553f..df936edac5c76 100644
--- a/drivers/gpu/drm/amd/display/dc/dce/dce_aux.c
+++ b/drivers/gpu/drm/amd/display/dc/dce/dce_aux.c
@@ -189,6 +189,12 @@ static void submit_channel_request(
 				1,
 				0);
 	}
+
+	REG_UPDATE(AUX_INTERRUPT_CONTROL, AUX_SW_DONE_ACK, 1);
+
+	REG_WAIT(AUX_SW_STATUS, AUX_SW_DONE, 0,
+				10, aux110->timeout_period/10);
+
 	/* set the delay and the number of bytes to write */
 
 	/* The length include
@@ -241,9 +247,6 @@ static void submit_channel_request(
 		}
 	}
 
-	REG_UPDATE(AUX_INTERRUPT_CONTROL, AUX_SW_DONE_ACK, 1);
-	REG_WAIT(AUX_SW_STATUS, AUX_SW_DONE, 0,
-				10, aux110->timeout_period/10);
 	REG_UPDATE(AUX_SW_CONTROL, AUX_SW_GO, 1);
 }
 
diff --git a/drivers/gpu/drm/amd/display/dc/dce/dce_aux.h b/drivers/gpu/drm/amd/display/dc/dce/dce_aux.h
index f7caab85dc801..2c6f50b4245a4 100644
--- a/drivers/gpu/drm/amd/display/dc/dce/dce_aux.h
+++ b/drivers/gpu/drm/amd/display/dc/dce/dce_aux.h
@@ -69,11 +69,11 @@ enum {	/* This is the timeout as defined in DP 1.2a,
 	 * at most within ~240usec. That means,
 	 * increasing this timeout will not affect normal operation,
 	 * and we'll timeout after
-	 * SW_AUX_TIMEOUT_PERIOD_MULTIPLIER * AUX_TIMEOUT_PERIOD = 1600usec.
+	 * SW_AUX_TIMEOUT_PERIOD_MULTIPLIER * AUX_TIMEOUT_PERIOD = 2400usec.
 	 * This timeout is especially important for
-	 * resume from S3 and CTS.
+	 * converters, resume from S3, and CTS.
 	 */
-	SW_AUX_TIMEOUT_PERIOD_MULTIPLIER = 4
+	SW_AUX_TIMEOUT_PERIOD_MULTIPLIER = 6
 };
 struct aux_engine_dce110 {
 	struct aux_engine base;
-- 
2.20.1