drm/amdgpu: Use transient mode during xcp switch

During partition switch, keep the state as transient mode. Fetch the
latest state if switch fails.
Signed-off-by: Lijo Lazar <lijo.lazar@amd.com>
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/amdgpu_xcp.c

@@ -139,7 +139,7 @@ static int __amdgpu_xcp_init(struct amdgpu_xcp_mgr *xcp_mgr, int num_xcps)
 
 int amdgpu_xcp_switch_partition_mode(struct amdgpu_xcp_mgr *xcp_mgr, int mode)
 {
-	int ret, num_xcps = 0;
+	int ret, curr_mode, num_xcps = 0;
 
 	if (!xcp_mgr || mode == AMDGPU_XCP_MODE_NONE)
 		return -EINVAL;
@@ -152,10 +152,22 @@ int amdgpu_xcp_switch_partition_mode(struct amdgpu_xcp_mgr *xcp_mgr, int mode)
 
 	mutex_lock(&xcp_mgr->xcp_lock);
 
+	curr_mode = xcp_mgr->mode;
+	/* State set to transient mode */
+	xcp_mgr->mode = AMDGPU_XCP_MODE_TRANS;
+
 	ret = xcp_mgr->funcs->switch_partition_mode(xcp_mgr, mode, &num_xcps);
 
-	if (ret)
+	if (ret) {
+		/* Failed, get whatever mode it's at now */
+		if (xcp_mgr->funcs->query_partition_mode)
+			xcp_mgr->mode = amdgpu_xcp_query_partition_mode(
+				xcp_mgr, AMDGPU_XCP_FL_LOCKED);
+		else
+			xcp_mgr->mode = curr_mode;
+
 		goto out;
+	}
 
 	if (!num_xcps || num_xcps > MAX_XCP) {
 		ret = -EINVAL;
@@ -183,7 +195,7 @@ int amdgpu_xcp_query_partition_mode(struct amdgpu_xcp_mgr *xcp_mgr, u32 flags)
 	if (!(flags & AMDGPU_XCP_FL_LOCKED))
 		mutex_lock(&xcp_mgr->xcp_lock);
 	mode = xcp_mgr->funcs->query_partition_mode(xcp_mgr);
-	if (mode != xcp_mgr->mode)
+	if (xcp_mgr->mode != AMDGPU_XCP_MODE_TRANS && mode != xcp_mgr->mode)
 		dev_WARN(
 			xcp_mgr->adev->dev,
 			"Cached partition mode %d not matching with device mode %d",

drivers/gpu/drm/amd/amdgpu/amdgpu_xcp.h

@@ -29,6 +29,7 @@
 #define MAX_XCP 8
 
 #define AMDGPU_XCP_MODE_NONE -1
+#define AMDGPU_XCP_MODE_TRANS -2
 
 #define AMDGPU_XCP_FL_NONE 0
 #define AMDGPU_XCP_FL_LOCKED (1 << 0)