From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Jun Lei <Jun.Lei@amd.com>,
        Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>,
        Mustapha Ghaddar <mustapha.ghaddar@amd.com>,
        Daniel Wheeler <daniel.wheeler@amd.com>,
        Alex Deucher <alexander.deucher@amd.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.15 35/42] drm/amd/display: Fix for the no Audio bug with Tiled Displays
Date:   Wed, 15 Dec 2021 18:21:16 +0100
Message-Id: <20211215172027.855542858@linuxfoundation.org>
In-Reply-To: <20211215172026.641863587@linuxfoundation.org>
References: <20211215172026.641863587@linuxfoundation.org>
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From: Mustapha Ghaddar <mghaddar@amd.com>

[ Upstream commit 5ceaebcda9061c04f439c93961f0819878365c0f ]

[WHY]
It seems like after a series of plug/unplugs we end up in a situation
where tiled display doesnt support Audio.

[HOW]
The issue seems to be related to when we check streams changed after an
HPD, we should be checking the audio_struct as well to see if any of its
values changed.

Reviewed-by: Jun Lei <Jun.Lei@amd.com>
Acked-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Signed-off-by: Mustapha Ghaddar <mustapha.ghaddar@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/gpu/drm/amd/display/dc/core/dc_resource.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_resource.c b/drivers/gpu/drm/amd/display/dc/core/dc_resource.c
index a60396d5be445..e94546187cf15 100644
--- a/drivers/gpu/drm/amd/display/dc/core/dc_resource.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_resource.c
@@ -1623,6 +1623,10 @@ bool dc_is_stream_unchanged(
 	if (old_stream->ignore_msa_timing_param != stream->ignore_msa_timing_param)
 		return false;
 
+	// Only Have Audio left to check whether it is same or not. This is a corner case for Tiled sinks
+	if (old_stream->audio_info.mode_count != stream->audio_info.mode_count)
+		return false;
+
 	return true;
 }
 
-- 
2.33.0