From: Wayne Lin <Wayne.Lin@amd.com>
Date: Sun, 20 Apr 2025 08:56:54 +0000 (+0800)
Subject: drm/amd/display: Remove incorrect checking in dmub aux handler
X-Git-Tag: v6.15-rc6~17^2~2^2~10
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=396dc51b3b7ea524bf8061f478332d0039e96d5d;p=thirdparty%2Flinux.git

drm/amd/display: Remove incorrect checking in dmub aux handler

[Why & How]
"Request length != reply length" is expected behavior defined in spec.
It's not an invalid reply. Besides, replied data handling logic is not
designed to be written in amdgpu_dm_process_dmub_aux_transfer_sync().
Remove the incorrectly handling section.

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>
(cherry picked from commit 81b5c6fa62af62fe89ae9576f41aae37830b94cb)
Cc: stable@vger.kernel.org
---

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 68bbe7d577735..d63f219de88ec 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -12764,19 +12764,9 @@ int amdgpu_dm_process_dmub_aux_transfer_sync(
 		payload->reply[0] = (adev->dm.dmub_notify->aux_reply.command >> 4) & 0xF;
 
 	if (!payload->write && p_notify->aux_reply.length &&
-			(payload->reply[0] == AUX_TRANSACTION_REPLY_AUX_ACK)) {
-
-		if (payload->length != p_notify->aux_reply.length) {
-			DRM_WARN("invalid read length %d from DPIA AUX 0x%x(%d)!\n",
-				p_notify->aux_reply.length,
-					payload->address, payload->length);
-			*operation_result = AUX_RET_ERROR_INVALID_REPLY;
-			goto out;
-		}
-
+			(payload->reply[0] == AUX_TRANSACTION_REPLY_AUX_ACK))
 		memcpy(payload->data, p_notify->aux_reply.data,
 				p_notify->aux_reply.length);
-	}
 
 	/* success */
 	ret = p_notify->aux_reply.length;