[PATCH 1/3] wip: drm/i915/display: Handle fused off display correctly

[José Roberto de Souza]

If all pipes are fused off it means that display is disabled, similar
like we handle for GEN 7 and 8 right above.

On GEN 9 the bit 31 is "Internal Graphics Disable" and on newer GENs
it has another function, probably on GEN 9 when bit 31 is set all
the 3 pipes disable bit are set, so we can unify the handling.

Cc: Lucas De Marchi <lucas.demarchi at intel.com>
Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
Signed-off-by: José Roberto de Souza <jose.souza at intel.com>
---
 drivers/gpu/drm/i915/i915_reg.h          |  1 +
 drivers/gpu/drm/i915/intel_device_info.c | 14 ++++++++++----
 2 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 0fb9030b89f1..5598b8636b29 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -7643,6 +7643,7 @@ enum {
 #define   CNL_DDI_CLOCK_REG_ACCESS_ON	(1 << 7)
 
 #define SKL_DFSM			_MMIO(0x51000)
+#define SKL_DFSM_INTERNAL_DISPLAY_DISABLE (1 << 30)
 #define SKL_DFSM_CDCLK_LIMIT_MASK	(3 << 23)
 #define SKL_DFSM_CDCLK_LIMIT_675	(0 << 23)
 #define SKL_DFSM_CDCLK_LIMIT_540	(1 << 23)
diff --git a/drivers/gpu/drm/i915/intel_device_info.c b/drivers/gpu/drm/i915/intel_device_info.c
index 85e480bdc673..eef12e48b339 100644
--- a/drivers/gpu/drm/i915/intel_device_info.c
+++ b/drivers/gpu/drm/i915/intel_device_info.c
@@ -972,15 +972,21 @@ void intel_device_info_runtime_init(struct drm_i915_private *dev_priv)
 			enabled_mask &= ~BIT(PIPE_D);
 
 		/*
-		 * At least one pipe should be enabled and if there are
-		 * disabled pipes, they should be the last ones, with no holes
-		 * in the mask.
+		 * If there are disabled pipes, they should be the last ones,
+		 * with no holes in the mask.
 		 */
-		if (enabled_mask == 0 || !is_power_of_2(enabled_mask + 1))
+		if (enabled_mask && !is_power_of_2(enabled_mask + 1))
 			DRM_ERROR("invalid pipe fuse configuration: enabled_mask=0x%x\n",
 				  enabled_mask);
 		else
 			info->pipe_mask = enabled_mask;
+
+		if ((IS_GEN9(dev_priv) && !IS_GEMINILAKE(dev_priv)) &&
+		    (dfsm & SKL_DFSM_INTERNAL_DISPLAY_DISABLE))
+			i915_modparams.disable_display = true;
+
+		if (!enabled_mask)
+			i915_modparams.disable_display = true;
 	}
 
 	/* Initialize slice/subslice/EU info */
-- 
2.23.0