drm/amd: Add concept of running prepare_suspend() sequence for IP blocks

If any IP blocks allocate memory during their hw_fini() sequence
this can cause the suspend to fail under memory pressure.  Introduce
a new phase that IP blocks can use to allocate memory before suspend
starts so that it can potentially be evicted into swap instead.
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -4348,7 +4348,7 @@ static int amdgpu_device_evict_resources(struct amdgpu_device *adev)
 int amdgpu_device_prepare(struct drm_device *dev)
 {
 	struct amdgpu_device *adev = drm_to_adev(dev);
-	int r;
+	int i, r;
 
 	if (dev->switch_power_state == DRM_SWITCH_POWER_OFF)
 		return 0;
@@ -4358,6 +4358,16 @@ int amdgpu_device_prepare(struct drm_device *dev)
 	if (r)
 		return r;
 
+	for (i = 0; i < adev->num_ip_blocks; i++) {
+		if (!adev->ip_blocks[i].status.valid)
+			continue;
+		if (!adev->ip_blocks[i].version->funcs->prepare_suspend)
+			continue;
+		r = adev->ip_blocks[i].version->funcs->prepare_suspend((void *)adev);
+		if (r)
+			return r;
+	}
+
 	return 0;
 }
 

drivers/gpu/drm/amd/include/amd_shared.h

@@ -299,6 +299,7 @@ struct amd_ip_funcs {
 	int (*hw_init)(void *handle);
 	int (*hw_fini)(void *handle);
 	void (*late_fini)(void *handle);
+	int (*prepare_suspend)(void *handle);
 	int (*suspend)(void *handle);
 	int (*resume)(void *handle);
 	bool (*is_idle)(void *handle);