[Intel-gfx] [PATCH] drm/i915: Remove unreachable code

[Vinicius Tinti]

By enabling -Wunreachable-code-aggressive on Clang the following code
paths are unreachable.

Commit ce22c320b8ca ("drm/i915/sdvo: convert to encoder disable/enable")
Commit 19f1f627b333 ("drm/i915/gt: Move ivb GT workarounds from
init_clock_gating to workarounds")
Commit 0a97015d45ee ("drm/i915: Compress GPU objects in error state")

By removing the unreachable code at
drivers/gpu/drm/i915/display/intel_sdvo.c the function
intel_sdvo_set_encoder_power_state becomes unused.

Commit ea5b213ad4b1 ("drm/i915: Subclass intel_encoder.")

Clang warns unreachable:

drivers/gpu/drm/i915/display/intel_sdvo.c:1768:3: warning: code will never
be executed [-Wunreachable-code]
                intel_sdvo_set_encoder_power_state(intel_sdvo,
                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/gpu/drm/i915/display/intel_sdvo.c:1767:6: note: silence by adding
parentheses to mark code as explicitly dead
        if (0)
            ^
            /* DISABLES CODE */ ( )
drivers/gpu/drm/i915/display/intel_sdvo.c:1852:3: warning: code will never
be executed [-Wunreachable-code]
                intel_sdvo_set_encoder_power_state(intel_sdvo,
                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/gpu/drm/i915/display/intel_sdvo.c:1851:6: note: silence by adding
parentheses to mark code as explicitly dead
        if (0)
            ^
            /* DISABLES CODE */ ( )

drivers/gpu/drm/i915/gt/intel_workarounds.c:884:3: warning: code will never
be executed [-Wunreachable-code]
                wa_masked_dis(wal, CACHE_MODE_0_GEN7, HIZ_RAW_STALL_OPT_DISABLE);
                ^~~~~~~~~~~~~
drivers/gpu/drm/i915/gt/intel_workarounds.c:882:6: note: silence by adding
parentheses to mark code as explicitly dead
        if (0) { /* causes HiZ corruption on ivb:gt1 */
            ^
            /* DISABLES CODE */ ( )

drivers/gpu/drm/i915/i915_gpu_error.c:319:11: warning: code will never be
executed [-Wunreachable-code]
        if (0 && zstream->total_out > zstream->total_in)
                 ^~~~~~~
drivers/gpu/drm/i915/i915_gpu_error.c:319:6: note: silence by adding
parentheses to mark code as explicitly dead
        if (0 && zstream->total_out > zstream->total_in)
            ^
            /* DISABLES CODE */ ( )

Clang warns unused after removing unreachable:

drivers/gpu/drm/i915/display/intel_sdvo.c:696:13: warning: unused function
'intel_sdvo_set_encoder_power_state' [-Wunused-function]
static bool intel_sdvo_set_encoder_power_state(struct intel_sdvo *intel_sdvo,
            ^

Signed-off-by: Vinicius Tinti <viniciustinti at gmail.com>
---
 drivers/gpu/drm/i915/display/intel_sdvo.c   | 30 ---------------------
 drivers/gpu/drm/i915/gt/intel_workarounds.c |  5 ----
 drivers/gpu/drm/i915/i915_gpu_error.c       |  4 ---
 3 files changed, 39 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_sdvo.c b/drivers/gpu/drm/i915/display/intel_sdvo.c
index 4eaa4aa86ecd..45d03b09f8f0 100644
--- a/drivers/gpu/drm/i915/display/intel_sdvo.c
+++ b/drivers/gpu/drm/i915/display/intel_sdvo.c
@@ -693,30 +693,6 @@ static bool intel_sdvo_get_active_outputs(struct intel_sdvo *intel_sdvo,
 				    outputs, sizeof(*outputs));
 }
 
-static bool intel_sdvo_set_encoder_power_state(struct intel_sdvo *intel_sdvo,
-					       int mode)
-{
-	u8 state = SDVO_ENCODER_STATE_ON;
-
-	switch (mode) {
-	case DRM_MODE_DPMS_ON:
-		state = SDVO_ENCODER_STATE_ON;
-		break;
-	case DRM_MODE_DPMS_STANDBY:
-		state = SDVO_ENCODER_STATE_STANDBY;
-		break;
-	case DRM_MODE_DPMS_SUSPEND:
-		state = SDVO_ENCODER_STATE_SUSPEND;
-		break;
-	case DRM_MODE_DPMS_OFF:
-		state = SDVO_ENCODER_STATE_OFF;
-		break;
-	}
-
-	return intel_sdvo_set_value(intel_sdvo,
-				    SDVO_CMD_SET_ENCODER_POWER_STATE, &state, sizeof(state));
-}
-
 static bool intel_sdvo_get_input_pixel_clock_range(struct intel_sdvo *intel_sdvo,
 						   int *clock_min,
 						   int *clock_max)
@@ -1764,9 +1740,6 @@ static void intel_disable_sdvo(struct intel_atomic_state *state,
 		intel_sdvo_disable_audio(intel_sdvo);
 
 	intel_sdvo_set_active_outputs(intel_sdvo, 0);
-	if (0)
-		intel_sdvo_set_encoder_power_state(intel_sdvo,
-						   DRM_MODE_DPMS_OFF);
 
 	temp = intel_de_read(dev_priv, intel_sdvo->sdvo_reg);
 
@@ -1848,9 +1821,6 @@ static void intel_enable_sdvo(struct intel_atomic_state *state,
 			    "sync\n", SDVO_NAME(intel_sdvo));
 	}
 
-	if (0)
-		intel_sdvo_set_encoder_power_state(intel_sdvo,
-						   DRM_MODE_DPMS_ON);
 	intel_sdvo_set_active_outputs(intel_sdvo, intel_sdvo->attached_output);
 
 	if (pipe_config->has_audio)
diff --git a/drivers/gpu/drm/i915/gt/intel_workarounds.c b/drivers/gpu/drm/i915/gt/intel_workarounds.c
index adc9a8ea410a..d60ff2c67138 100644
--- a/drivers/gpu/drm/i915/gt/intel_workarounds.c
+++ b/drivers/gpu/drm/i915/gt/intel_workarounds.c
@@ -879,11 +879,6 @@ ivb_gt_workarounds_init(struct drm_i915_private *i915, struct i915_wa_list *wal)
 			   GEN7_FF_VS_SCHED_HW |
 			   GEN7_FF_DS_SCHED_HW);
 
-	if (0) { /* causes HiZ corruption on ivb:gt1 */
-		/* enable HiZ Raw Stall Optimization */
-		wa_masked_dis(wal, CACHE_MODE_0_GEN7, HIZ_RAW_STALL_OPT_DISABLE);
-	}
-
 	/* WaDisable4x2SubspanOptimization:ivb */
 	wa_masked_en(wal, CACHE_MODE_1, PIXEL_SUBSPAN_COLLECT_OPT_DISABLE);
 
diff --git a/drivers/gpu/drm/i915/i915_gpu_error.c b/drivers/gpu/drm/i915/i915_gpu_error.c
index d8cac4c5881f..6ec699da1dc2 100644
--- a/drivers/gpu/drm/i915/i915_gpu_error.c
+++ b/drivers/gpu/drm/i915/i915_gpu_error.c
@@ -315,10 +315,6 @@ static int compress_page(struct i915_vma_compress *c,
 		cond_resched();
 	} while (zstream->avail_in);
 
-	/* Fallback to uncompressed if we increase size? */
-	if (0 && zstream->total_out > zstream->total_in)
-		return -E2BIG;
-
 	return 0;
 }
 
-- 
2.25.1