drm/amd/display: Fix compiler warnings on high compiler warning levels

[why]
Enabling higher compiler warning levels results in many issues that can
be trivially resolved as well as some potentially critical issues.

[how]
Fix all compiler warnings found with various compilers and higher
warning levels. Primarily, potentially uninitialized variables and
unreachable code.

Reviewed-by: Leo Li <[e-mail]>
Acked-by: Roman Li <[e-mail]>
Signed-off-by: Aric Cyr <[e-mail]>
Signed-off-by: Alex Deucher <[e-mail]>

drivers/gpu/drm/amd/display/dc/bios/bios_parser2.c

···
 		return (le16_to_cpu(bp->object_info_tbl.v1_5->supporteddevices) & mask) != 0;
 		break;
 	}
-
-	return false;
 }
 
 static uint32_t bios_parser_get_ss_entry_number(

drivers/gpu/drm/amd/display/dc/clk_mgr/dcn21/rn_clk_mgr.c

···
 
 	j = -1;
 
-	ASSERT(PP_SMU_NUM_FCLK_DPM_LEVELS <= MAX_NUM_DPM_LVL);
+	static_assert(PP_SMU_NUM_FCLK_DPM_LEVELS <= MAX_NUM_DPM_LVL,
+		"number of reported FCLK DPM levels exceed maximum");
 
 	/* Find lowest DPM, FCLK is filled in reverse order*/
 

drivers/gpu/drm/amd/display/dc/clk_mgr/dcn301/vg_clk_mgr.c

···
 
 	j = -1;
 
-	ASSERT(VG_NUM_FCLK_DPM_LEVELS <= MAX_NUM_DPM_LVL);
+	static_assert(VG_NUM_FCLK_DPM_LEVELS <= MAX_NUM_DPM_LVL,
+		"number of reported FCLK DPM levels exceeds maximum");
 
 	/* Find lowest DPM, FCLK is filled in reverse order*/
 

drivers/gpu/drm/amd/display/dc/clk_mgr/dcn31/dcn31_clk_mgr.c

···
 
 	j = -1;
 
-	ASSERT(NUM_DF_PSTATE_LEVELS <= MAX_NUM_DPM_LVL);
+	static_assert(NUM_DF_PSTATE_LEVELS <= MAX_NUM_DPM_LVL,
+		"number of reported pstate levels exceeds maximum");
 
 	/* Find lowest DPM, FCLK is filled in reverse order*/
 

drivers/gpu/drm/amd/display/dc/clk_mgr/dcn316/dcn316_clk_mgr.c

···
 
 	j = -1;
 
-	ASSERT(NUM_DF_PSTATE_LEVELS <= MAX_NUM_DPM_LVL);
+	static_assert(NUM_DF_PSTATE_LEVELS <= MAX_NUM_DPM_LVL,
+		"number of reported pstate levels exceeds maximum");
 
 	/* Find lowest DPM, FCLK is filled in reverse order*/
 

drivers/gpu/drm/amd/display/dc/core/dc_hw_sequencer.c

···
 		struct dc_dmub_cmd *dc_dmub_cmd,
 		unsigned int dmub_cmd_count,
 		struct block_sequence block_sequence[],
-		int *num_steps,
+		unsigned int *num_steps,
 		struct pipe_ctx *pipe_ctx,
 		struct dc_stream_status *stream_status)
 {

drivers/gpu/drm/amd/display/dc/dc_dmub_srv.c

···
 static void dc_dmub_srv_exit_low_power_state(const struct dc *dc)
 {
 	struct dc_dmub_srv *dc_dmub_srv;
-	uint32_t rcg_exit_count, ips1_exit_count, ips2_exit_count;
+	uint32_t rcg_exit_count = 0, ips1_exit_count = 0, ips2_exit_count = 0;
 
 	if (dc->debug.dmcub_emulation)
 		return;

drivers/gpu/drm/amd/display/dc/dce/dce_transform.c

···
 static void program_pwl(struct dce_transform *xfm_dce,
 			const struct pwl_params *params)
 {
-	int retval;
+	uint32_t retval;
 	uint8_t max_tries = 10;
 	uint8_t counter = 0;
 	uint32_t i = 0;

drivers/gpu/drm/amd/display/dc/dcn10/dcn10_link_encoder.c

···
 	default:
 		return SIGNAL_TYPE_NONE;
 	}
-	return SIGNAL_TYPE_NONE;
 }
 
 void dcn10_link_encoder_get_max_link_cap(struct link_encoder *enc,

drivers/gpu/drm/amd/display/dc/dcn32/dcn32_resource_helpers.c

···
 {
 	int i, pipe_cnt;
 	struct resource_context *res_ctx = &context->res_ctx;
-	struct pipe_ctx *pipe;
+	struct pipe_ctx *pipe = 0;
 	bool disable_unbounded_requesting = dc->debug.disable_z9_mpc || dc->debug.disable_unbounded_requesting;
 
 	for (i = 0, pipe_cnt = 0; i < dc->res_pool->pipe_count; i++) {

drivers/gpu/drm/amd/display/dc/dcn35/dcn35_dio_link_encoder.c

···
 	default:
 		return SIGNAL_TYPE_NONE;
 	}
-	return SIGNAL_TYPE_NONE;
 }
 
 void dcn35_link_encoder_setup(

drivers/gpu/drm/amd/display/dc/dml/dcn20/dcn20_fpu.c

···
 	} else {
 		return DCN_ZSTATE_SUPPORT_DISALLOW;
 	}
-
-	return DCN_ZSTATE_SUPPORT_DISALLOW;
 }
 
 static void dcn20_adjust_freesync_v_startup(

drivers/gpu/drm/amd/display/dc/dml/dcn30/display_mode_vba_30.c

···
 			return DesiredBPP;
 		}
 	}
-	return BPP_INVALID;
 }
 
 void dml30_ModeSupportAndSystemConfigurationFull(struct display_mode_lib *mode_lib)

drivers/gpu/drm/amd/display/dc/dml/dcn31/display_mode_vba_31.c

···
 			return DesiredBPP;
 		}
 	}
-	return BPP_INVALID;
 }
 
 static noinline void CalculatePrefetchSchedulePerPlane(

drivers/gpu/drm/amd/display/dc/dml/dcn314/dcn314_fpu.c

···
 {
 	int i, pipe_cnt;
 	struct resource_context *res_ctx = &context->res_ctx;
-	struct pipe_ctx *pipe;
+	struct pipe_ctx *pipe = 0;
 	bool upscaled = false;
 	const unsigned int max_allowed_vblank_nom = 1023;
 

drivers/gpu/drm/amd/display/dc/dml/dcn314/display_mode_vba_314.c

···
 			return DesiredBPP;
 		}
 	}
-	return BPP_INVALID;
 }
 
 static noinline void CalculatePrefetchSchedulePerPlane(

drivers/gpu/drm/amd/display/dc/dml/dcn32/display_mode_vba_util_32.c

···
 			MaxLinkBPP = 2 * MaxLinkBPP;
 	}
 
+	*RequiredSlots = dml_ceil(DesiredBPP / MaxLinkBPP * 64, 1);
+
 	if (DesiredBPP == 0) {
 		if (DSCEnable) {
 			if (MaxLinkBPP < MinDSCBPP)
···
 		else
 			return DesiredBPP;
 	}
-
-	*RequiredSlots = dml_ceil(DesiredBPP / MaxLinkBPP * 64, 1);
-
-	return BPP_INVALID;
 } // TruncToValidBPP
 
 double dml32_RequiredDTBCLK(
···
 	unsigned int i, j, k;
 	unsigned int SurfaceWithMinActiveFCLKChangeMargin = 0;
 	unsigned int DRAMClockChangeSupportNumber = 0;
-	unsigned int LastSurfaceWithoutMargin;
+	unsigned int LastSurfaceWithoutMargin = 0;
 	unsigned int DRAMClockChangeMethod = 0;
 	bool FoundFirstSurfaceWithMinActiveFCLKChangeMargin = false;
 	double MinActiveFCLKChangeMargin = 0.;
···
 	double LastZ8StutterPeriod = 0.0;
 	double LastStutterPeriod = 0.0;
 	unsigned int TotalNumberOfActiveOTG = 0;
-	double doublePixelClock;
-	unsigned int doubleHTotal;
-	unsigned int doubleVTotal;
+	double doublePixelClock = 0;
+	unsigned int doubleHTotal = 0;
+	unsigned int doubleVTotal = 0;
 	bool SameTiming = true;
 	double DETBufferingTimeY;
 	double SwathWidthYCriticalSurface = 0.0;

drivers/gpu/drm/amd/display/dc/dml/dcn35/dcn35_fpu.c

···
 {
 	int i, pipe_cnt;
 	struct resource_context *res_ctx = &context->res_ctx;
-	struct pipe_ctx *pipe;
+	struct pipe_ctx *pipe = 0;
 	bool upscaled = false;
 	const unsigned int max_allowed_vblank_nom = 1023;
 

drivers/gpu/drm/amd/display/dc/dml/dcn351/dcn351_fpu.c

···
 {
 	int i, pipe_cnt;
 	struct resource_context *res_ctx = &context->res_ctx;
-	struct pipe_ctx *pipe;
+	struct pipe_ctx *pipe = 0;
 	bool upscaled = false;
 	const unsigned int max_allowed_vblank_nom = 1023;
 

drivers/gpu/drm/amd/display/dc/dml2/display_mode_core.c

···
 		}
 	}
 
+	*RequiredSlots = (dml_uint_t)(dml_ceil(DesiredBPP / MaxLinkBPP * 64, 1));
+
 	if (DesiredBPP == 0) {
 		if (DSCEnable) {
 			if (MaxLinkBPP < MinDSCBPP) {
···
 			return DesiredBPP;
 		}
 	}
-
-	*RequiredSlots = (dml_uint_t)(dml_ceil(DesiredBPP / MaxLinkBPP * 64, 1));
-
-	return __DML_DPP_INVALID__;
 } // TruncToValidBPP
 
 static void CalculateWatermarksMALLUseAndDRAMSpeedChangeSupport(
···
 	dml_bool_t FoundCriticalSurface = false;
 
 	dml_uint_t TotalNumberOfActiveOTG = 0;
-	dml_float_t SinglePixelClock;
-	dml_uint_t SingleHTotal;
-	dml_uint_t SingleVTotal;
+	dml_float_t SinglePixelClock = 0;
+	dml_uint_t SingleHTotal = 0;
+	dml_uint_t SingleVTotal = 0;
 	dml_bool_t SameTiming = true;
 
 	dml_float_t LastStutterPeriod = 0.0;

drivers/gpu/drm/amd/display/dc/dml2/dml2_utils.c

···
 static bool get_plane_id(struct dml2_context *dml2, const struct dc_state *state, const struct dc_plane_state *plane,
 	unsigned int stream_id, unsigned int plane_index, unsigned int *plane_id)
 {
-	int i, j;
+	unsigned int i, j;
 	bool is_plane_duplicate = dml2->v20.scratch.plane_duplicate_exists;
 
 	if (!plane_id)

drivers/gpu/drm/amd/display/dc/dsc/dc_dsc.c

···
 	bool is_dsc_possible = false;
 	struct dsc_enc_caps dsc_enc_caps;
 	struct dsc_enc_caps dsc_common_caps;
-	struct dc_dsc_config config;
+	struct dc_dsc_config config = {0};
 	struct dc_dsc_config_options options = {0};
 
 	options.dsc_min_slice_height_override = dsc_min_slice_height_override;
···
 		struct dc_dsc_config *dsc_cfg)
 {
 	struct dsc_enc_caps dsc_common_caps;
-	int max_slices_h;
-	int min_slices_h;
-	int num_slices_h;
+	int max_slices_h = 0;
+	int min_slices_h = 0;
+	int num_slices_h = 0;
 	int pic_width;
 	int slice_width;
 	int target_bpp;

drivers/gpu/drm/amd/display/dc/hwss/dce110/dce110_hwseq.c

···
 		struct dc *dc,
 		struct dc_state *context)
 {
-	int i;
+	unsigned int i;
 
 	/* program audio wall clock. use HDMI as clock source if HDMI
 	 * audio active. Otherwise, use DP as clock source

drivers/gpu/drm/amd/display/dc/hwss/dcn30/dcn30_hwseq.c

···
 {
 	union dmub_rb_cmd cmd;
 	uint32_t tmr_delay = 0, tmr_scale = 0;
-	struct dc_cursor_attributes cursor_attr;
+	struct dc_cursor_attributes cursor_attr = {0};
 	bool cursor_cache_enable = false;
 	struct dc_stream_state *stream = NULL;
 	struct dc_plane_state *plane = NULL;

drivers/gpu/drm/amd/display/dc/hwss/hw_sequencer.h

···
 		struct dc_dmub_cmd *dc_dmub_cmd,
 		unsigned int dmub_cmd_count,
 		struct block_sequence block_sequence[],
-		int *num_steps,
+		unsigned int *num_steps,
 		struct pipe_ctx *pipe_ctx,
 		struct dc_stream_status *stream_status);
 

drivers/gpu/drm/amd/display/dc/link/accessories/link_dp_cts.c

···
 {
 	int i;
 	struct pipe_ctx *pipe;
-	struct dc_stream_state *link_stream;
+	struct dc_stream_state *link_stream = 0;
 	struct dc_link_settings store_settings = *link_setting;
 
 	link->preferred_link_setting = store_settings;

drivers/gpu/drm/amd/display/dc/link/link_dpms.c

···
 		if (link->ep_type == DISPLAY_ENDPOINT_PHY &&
 			link->link_enc->funcs->get_dig_frontend &&
 			link->link_enc->funcs->is_dig_enabled(link->link_enc)) {
-			unsigned int fe = link->link_enc->funcs->get_dig_frontend(link->link_enc);
+			int fe = link->link_enc->funcs->get_dig_frontend(link->link_enc);
 
 			if (fe != ENGINE_ID_UNKNOWN)
 				for (j = 0; j < dc->res_pool->stream_enc_count; j++) {

drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_training_dpia.c

···
 {
 	enum link_training_result result = LINK_TRAINING_CR_FAIL_LANE0;
 	uint8_t repeater_cnt = 0; /* Number of hops/repeaters in display path. */
-	enum dc_status status;
+	enum dc_status status = DC_ERROR_UNEXPECTED;
 	uint32_t retries_cr = 0; /* Number of consecutive attempts with same VS or PE. */
 	uint32_t retry_count = 0;
 	uint32_t wait_time_microsec = TRAINING_AUX_RD_INTERVAL; /* From DP spec, CR read interval is always 100us. */
···
 	enum link_training_result result = LINK_TRAINING_EQ_FAIL_EQ;
 	uint8_t repeater_cnt = 0; /* Number of hops/repeaters in display path. */
 	uint32_t retries_eq = 0;
-	enum dc_status status;
+	enum dc_status status = DC_ERROR_UNEXPECTED;
 	enum dc_dp_training_pattern tr_pattern;
 	uint32_t wait_time_microsec = 0;
 	enum dc_lane_count lane_count = lt_settings->link_settings.lane_count;

drivers/gpu/drm/amd/display/dc/resource/dce112/dce112_resource.c

···
 	default:
 		return NULL;
 	}
-
-	return NULL;
 }
 
 static enum dc_status build_mapped_resource(

drivers/gpu/drm/amd/display/dc/resource/dce120/dce120_resource.c

···
 	struct irq_service_init_data irq_init_data;
 	static const struct resource_create_funcs *res_funcs;
 	bool is_vg20 = ASICREV_IS_VEGA20_P(ctx->asic_id.hw_internal_rev);
-	uint32_t pipe_fuses;
+	uint32_t pipe_fuses = 0;
 
 	ctx->dc_bios->regs = &bios_regs;
 

drivers/gpu/drm/amd/display/dc/resource/dcn30/dcn30_resource.c

···
 	int split[MAX_PIPES] = { 0 };
 	bool merge[MAX_PIPES] = { false };
 	bool newly_split[MAX_PIPES] = { false };
-	int pipe_cnt, i, pipe_idx, vlevel;
+	int pipe_cnt, i, pipe_idx, vlevel = 0;
 	struct vba_vars_st *vba = &context->bw_ctx.dml.vba;
 
 	ASSERT(pipes);

drivers/gpu/drm/amd/display/dc/resource/dcn31/dcn31_resource.c

···
 {
 	int i, pipe_cnt;
 	struct resource_context *res_ctx = &context->res_ctx;
-	struct pipe_ctx *pipe;
+	struct pipe_ctx *pipe = 0;
 	bool upscaled = false;
 
 	DC_FP_START();

drivers/gpu/drm/amd/display/dc/resource/dcn316/dcn316_resource.c

···
 {
 	int i, pipe_cnt;
 	struct resource_context *res_ctx = &context->res_ctx;
-	struct pipe_ctx *pipe;
+	struct pipe_ctx *pipe = 0;
 	const int max_usable_det = context->bw_ctx.dml.ip.config_return_buffer_size_in_kbytes - DCN3_16_MIN_COMPBUF_SIZE_KB;
 
 	DC_FP_START();

drivers/gpu/drm/amd/display/modules/color/color_gamma.c

···
 	struct fixed31_32 min_display;
 	struct fixed31_32 max_content;
 	struct fixed31_32 clip = dc_fixpt_one;
-	struct fixed31_32 output;
+	struct fixed31_32 output = dc_fixpt_zero;
 	bool use_eetf = false;
 	bool is_clipped = false;
 	struct fixed31_32 sdr_white_level;

drivers/gpu/drm/amd/display/modules/hdcp/hdcp2_execution.c

···
 
 static enum mod_hdcp_status poll_l_prime_available(struct mod_hdcp *hdcp)
 {
-	enum mod_hdcp_status status;
+	enum mod_hdcp_status status = MOD_HDCP_STATUS_FAILURE;
 	uint8_t size;
 	uint16_t max_wait = 20; // units of ms
 	uint16_t num_polls = 5;