From: Wayne Lin <Wayne.Lin@amd.com>
Date: Fri, 18 Apr 2025 08:31:59 +0000 (+0800)
Subject: drm/amd/display: Shift DMUB AUX reply command if necessary
X-Git-Tag: v6.16-rc1~144^2~10^2~51
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=d5c9ade755a9afa210840708a12a8f44c0d532f4;p=thirdparty%2Fkernel%2Flinux.git

drm/amd/display: Shift DMUB AUX reply command if necessary

[Why]
Defined value of dmub AUX reply command field get updated but didn't
adjust dm receiving side accordingly.

[How]
Check the received reply command value to see if it's updated version
or not. Adjust it if necessary.

Fixes: ead08b95fa50 ("drm/amd/display: Fix race condition in DPIA AUX transfer")
Cc: Mario Limonciello <mario.limonciello@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Ray Wu <ray.wu@amd.com>
Signed-off-by: Wayne Lin <Wayne.Lin@amd.com>
Signed-off-by: Ray Wu <ray.wu@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
---

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 f531bb3bf3d30..31894e52f3079 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -12848,8 +12848,11 @@ int amdgpu_dm_process_dmub_aux_transfer_sync(
 		goto out;
 	}
 
+	payload->reply[0] = adev->dm.dmub_notify->aux_reply.command & 0xF;
+	if (adev->dm.dmub_notify->aux_reply.command & 0xF0)
+		/* The reply is stored in the top nibble of the command. */
+		payload->reply[0] = (adev->dm.dmub_notify->aux_reply.command >> 4) & 0xF;
 
-	payload->reply[0] = adev->dm.dmub_notify->aux_reply.command;
 	if (!payload->write && p_notify->aux_reply.length &&
 			(payload->reply[0] == AUX_TRANSACTION_REPLY_AUX_ACK)) {