linux-kernel - [PATCH AUTOSEL 5.15 18/29] drm/amd/display: Reset DMCUB before HW init

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Date:   Mon, 20 Dec 2021 20:57:39 -0500
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Nicholas Kazlauskas <nicholas.kazlauskas@....com>,
        Aurabindo Jayamohanan Pillai <Aurabindo.Pillai@....com>,
        Pavle Kotarac <Pavle.Kotarac@....com>,
        Daniel Wheeler <daniel.wheeler@....com>,
        Alex Deucher <alexander.deucher@....com>,
        Sasha Levin <sashal@...nel.org>, harry.wentland@....com,
        sunpeng.li@....com, christian.koenig@....com, Xinhui.Pan@....com,
        airlied@...ux.ie, daniel@...ll.ch, Rodrigo.Siqueira@....com,
        Anson.Jacob@....com, qingqing.zhuo@....com, Roman.Li@....com,
        aurabindo.pillai@....com, nikola.cornij@....com,
        stylon.wang@....com, amd-gfx@...ts.freedesktop.org,
        dri-devel@...ts.freedesktop.org
Subject: [PATCH AUTOSEL 5.15 18/29] drm/amd/display: Reset DMCUB before HW init

From: Nicholas Kazlauskas <nicholas.kazlauskas@....com>

[ Upstream commit 791255ca9fbe38042cfd55df5deb116dc11fef18 ]

[Why]
If the firmware wasn't reset by PSP or HW and is currently running
then the firmware will hang or perform underfined behavior when we
modify its firmware state underneath it.

[How]
Reset DMCUB before setting up cache windows and performing HW init.

Reviewed-by: Aurabindo Jayamohanan Pillai <Aurabindo.Pillai@....com>
Acked-by: Pavle Kotarac <Pavle.Kotarac@....com>
Tested-by: Daniel Wheeler <daniel.wheeler@....com>
Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas@....com>
Signed-off-by: Alex Deucher <alexander.deucher@....com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index fef13e93a99fd..bdc894bd66e31 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -900,6 +900,11 @@ static int dm_dmub_hw_init(struct amdgpu_device *adev)
 		return 0;
 	}
 
+	/* Reset DMCUB if it was previously running - before we overwrite its memory. */
+	status = dmub_srv_hw_reset(dmub_srv);
+	if (status != DMUB_STATUS_OK)
+		DRM_WARN("Error resetting DMUB HW: %d\n", status);
+
 	hdr = (const struct dmcub_firmware_header_v1_0 *)dmub_fw->data;
 
 	fw_inst_const = dmub_fw->data +
-- 
2.34.1