drm/amd/display: Add DC Debug mask to disable features for bringup

[Why]
At bringup we want to be able to disable various power features.

[How]
These features are already exposed as dc_debug_options and exercised
on other OSes. Create a new dc_debug_mask module parameter and expose
relevant bits, in particular
 * DC_DISABLE_PIPE_SPLIT
 * DC_DISABLE_STUTTER
 * DC_DISABLE_DSC
 * DC_DISABLE_CLOCK_GATING
Signed-off-by: Harry Wentland <harry.wentland@amd.com>
Reviewed-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -173,6 +173,7 @@ extern int amdgpu_gpu_recovery;
 extern int amdgpu_emu_mode;
 extern uint amdgpu_smu_memory_pool_size;
 extern uint amdgpu_dc_feature_mask;
+extern uint amdgpu_dc_debug_mask;
 extern uint amdgpu_dm_abm_level;
 extern struct amdgpu_mgpu_info mgpu_info;
 extern int amdgpu_ras_enable;

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

@@ -140,6 +140,7 @@ int amdgpu_emu_mode = 0;
 uint amdgpu_smu_memory_pool_size = 0;
 /* FBC (bit 0) disabled by default*/
 uint amdgpu_dc_feature_mask = 0;
+uint amdgpu_dc_debug_mask = 0;
 int amdgpu_async_gfx_ring = 1;
 int amdgpu_mcbp = 0;
 int amdgpu_discovery = -1;
@@ -714,6 +715,13 @@ MODULE_PARM_DESC(queue_preemption_timeout_ms, "queue preemption timeout in ms (1
 MODULE_PARM_DESC(dcfeaturemask, "all stable DC features enabled (default))");
 module_param_named(dcfeaturemask, amdgpu_dc_feature_mask, uint, 0444);
 
+/**
+ * DOC: dcdebugmask (uint)
+ * Override display features enabled. See enum DC_DEBUG_MASK in drivers/gpu/drm/amd/include/amd_shared.h.
+ */
+MODULE_PARM_DESC(dcdebugmask, "all debug options disabled (default))");
+module_param_named(dcdebugmask, amdgpu_dc_debug_mask, uint, 0444);
+
 /**
  * DOC: abmlevel (uint)
  * Override the default ABM (Adaptive Backlight Management) level used for DC

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c

@@ -918,6 +918,20 @@ static int amdgpu_dm_init(struct amdgpu_device *adev)
 		goto error;
 	}
 
+	if (amdgpu_dc_debug_mask & DC_DISABLE_PIPE_SPLIT) {
+		adev->dm.dc->debug.force_single_disp_pipe_split = false;
+		adev->dm.dc->debug.pipe_split_policy = MPC_SPLIT_AVOID;
+	}
+
+	if (amdgpu_dc_debug_mask & DC_DISABLE_STUTTER)
+		adev->dm.dc->debug.disable_stutter = true;
+
+	if (amdgpu_dc_debug_mask & DC_DISABLE_DSC)
+		adev->dm.dc->debug.disable_dsc = true;
+
+	if (amdgpu_dc_debug_mask & DC_DISABLE_CLOCK_GATING)
+		adev->dm.dc->debug.disable_clock_gate = true;
+
 	r = dm_dmub_hw_init(adev);
 	if (r) {
 		DRM_ERROR("DMUB interface failed to initialize: status=%d\n", r);

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

@@ -150,6 +150,13 @@ enum DC_FEATURE_MASK {
 	DC_PSR_MASK = 0x8,
 };
 
+enum DC_DEBUG_MASK {
+	DC_DISABLE_PIPE_SPLIT = 0x1,
+	DC_DISABLE_STUTTER = 0x2,
+	DC_DISABLE_DSC = 0x4,
+	DC_DISABLE_CLOCK_GATING = 0x8
+};
+
 enum amd_dpm_forced_level;
 /**
  * struct amd_ip_funcs - general hooks for managing amdgpu IP Blocks