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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, Daniel Wheeler <daniel.wheeler@amd.com>,
        Anthony Koo <Anthony.Koo@amd.com>,
        Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>,
        Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>,
        Alex Deucher <alexander.deucher@amd.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.16 016/285] drm/amd/display: Use PSR version selected during set_psr_caps
Date:   Tue, 12 Apr 2022 08:27:53 +0200
Message-Id: <20220412062944.145935933@linuxfoundation.org>
In-Reply-To: <20220412062943.670770901@linuxfoundation.org>
References: <20220412062943.670770901@linuxfoundation.org>
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From: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>

[ Upstream commit b80ddeb29d9df449f875f0b6f5de08d7537c02b8 ]

[Why]
If the DPCD caps specifies a PSR version newer than PSR_VERSION_1 then
we fallback to using PSR_VERSION_1 in amdgpu_dm_set_psr_caps.

This gets overriden with the raw DPCD value in amdgpu_dm_link_setup_psr,
which can result in DMCUB hanging if we pass in an unsupported PSR
version number.

[How]
Fix the hang by using link->psr_settings.psr_version directly during
amdgpu_dm_link_setup_psr.

Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Reviewed-by: Anthony Koo <Anthony.Koo@amd.com>
Acked-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_psr.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_psr.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_psr.c
index c022e56f9459..90962fb91916 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_psr.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_psr.c
@@ -74,10 +74,8 @@ bool amdgpu_dm_link_setup_psr(struct dc_stream_state *stream)
 
 	link = stream->link;
 
-	psr_config.psr_version = link->dpcd_caps.psr_caps.psr_version;
-
-	if (psr_config.psr_version > 0) {
-		psr_config.psr_exit_link_training_required = 0x1;
+	if (link->psr_settings.psr_version != DC_PSR_VERSION_UNSUPPORTED) {
+		psr_config.psr_version = link->psr_settings.psr_version;
 		psr_config.psr_frame_capture_indication_req = 0;
 		psr_config.psr_rfb_setup_time = 0x37;
 		psr_config.psr_sdp_transmit_line_num_deadline = 0x20;
-- 
2.35.1