[Intel-gfx] [PATCH v2] drm/i915: Handle PipeC fused off on GEN7+

[Gabriel Feceoru]

Starting with Gen7 (IVB) Display PipeC can be fused off on some production
parts. When disabled, display hardware will prevent the pipe C register bit
from being set to 1.

Fixed by adjusting pipe_count to reflect this.

Signed-off-by: Gabriel Feceoru <gabriel.feceoru at intel.com>
---
 drivers/gpu/drm/i915/i915_dma.c | 3 +++
 drivers/gpu/drm/i915/i915_reg.h | 1 +
 2 files changed, 4 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
index 44a896c..c3b93e7 100644
--- a/drivers/gpu/drm/i915/i915_dma.c
+++ b/drivers/gpu/drm/i915/i915_dma.c
@@ -813,6 +813,9 @@ static void intel_device_info_runtime_init(struct drm_device *dev)
 		     !(sfuse_strap & SFUSE_STRAP_FUSE_LOCK))) {
 			DRM_INFO("Display fused off, disabling\n");
 			info->num_pipes = 0;
+		} else if (I915_READ(FUSE_STRAP) & IVB_PIPE_C_DISABLE) {
+			DRM_INFO("PipeC fused off\n");
+			info->num_pipes -= 1;
 		}
 	}
 
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 0a98889..a182739 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -5945,6 +5945,7 @@ enum skl_disp_power_wells {
 #define  ILK_INTERNAL_GRAPHICS_DISABLE	(1 << 31)
 #define  ILK_INTERNAL_DISPLAY_DISABLE	(1 << 30)
 #define  ILK_DISPLAY_DEBUG_DISABLE	(1 << 29)
+#define  IVB_PIPE_C_DISABLE		(1 << 28)
 #define  ILK_HDCP_DISABLE		(1 << 25)
 #define  ILK_eDP_A_DISABLE		(1 << 24)
 #define  HSW_CDCLK_LIMIT		(1 << 24)
-- 
1.9.1