drm/amdgpu: add module parameter for async_gfx_ring enablement

0 means disable async_gfx_ring and is the default setting
1 means enable async_gfx_ring
Signed-off-by: Hawking Zhang <Hawking.Zhang@amd.com>
Reviewed-by: Jack Xiao <jack.xiao@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -158,6 +158,7 @@ extern uint amdgpu_dm_abm_level;
 extern struct amdgpu_mgpu_info mgpu_info;
 extern int amdgpu_ras_enable;
 extern uint amdgpu_ras_mask;
+extern int amdgpu_async_gfx_ring;
 
 #ifdef CONFIG_DRM_AMDGPU_SI
 extern int amdgpu_si_support;

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

@@ -136,6 +136,7 @@ int amdgpu_emu_mode = 0;
 uint amdgpu_smu_memory_pool_size = 0;
 /* FBC (bit 0) disabled by default*/
 uint amdgpu_dc_feature_mask = 0;
+int amdgpu_async_gfx_ring = 0;
 
 struct amdgpu_mgpu_info mgpu_info = {
 	.mutex = __MUTEX_INITIALIZER(mgpu_info.mutex),
@@ -565,6 +566,14 @@ MODULE_PARM_DESC(smu_memory_pool_size,
 		"0x1 = 256Mbyte, 0x2 = 512Mbyte, 0x4 = 1 Gbyte, 0x8 = 2GByte");
 module_param_named(smu_memory_pool_size, amdgpu_smu_memory_pool_size, uint, 0444);
 
+/**
+ * DOC: async_gfx_ring (int)
+ * It is used to enable gfx rings that could be configured with different prioritites or equal priorities
+ */
+MODULE_PARM_DESC(async_gfx_ring,
+	"Asynchronous GFX rings that could be configured with either different priorities (HP3D ring and LP3D ring), or equal priorities (0 = disabled (default), 1 = enabled)");
+module_param_named(async_gfx_ring, amdgpu_async_gfx_ring, int, 0444);
+
 #ifdef CONFIG_HSA_AMD
 /**
  * DOC: sched_policy (int)