drm/amdgpu: enable MULTI_MON_PP_MCLK_SWITCH DC feature at default

With this, for multiple monitors in sync(e.g. with the same model),
mclk switching will be allowed. That helps saving some idle power on
some ASICs(e.g. Polaris).
Signed-off-by: Evan Quan <evan.quan@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -140,8 +140,16 @@ int amdgpu_compute_multipipe = -1;
 int amdgpu_gpu_recovery = -1; /* auto */
 int amdgpu_emu_mode = 0;
 uint amdgpu_smu_memory_pool_size = 0;
-/* FBC (bit 0) disabled by default*/
-uint amdgpu_dc_feature_mask = 0;
+/*
+ * FBC (bit 0) disabled by default
+ * MULTI_MON_PP_MCLK_SWITCH (bit 1) enabled by default
+ *   - With this, for multiple monitors in sync(e.g. with the same model),
+ *     mclk switching will be allowed. And the mclk will be not foced to the
+ *     highest. That helps saving some idle power.
+ * DISABLE_FRACTIONAL_PWM (bit 2) disabled by default
+ * PSR (bit 3) disabled by default
+ */
+uint amdgpu_dc_feature_mask = 2;
 uint amdgpu_dc_debug_mask = 0;
 int amdgpu_async_gfx_ring = 1;
 int amdgpu_mcbp = 0;