FUSE_STRAP has a bit to inform us that the display has been fused off.
Use it to setup the definitive number of pipes at run-time.
v2: actually tweak num_pipes, not num_planes
v3: also tests SFUSE_STRAP bit 7
Signed-off-by: Damien Lespiau <damien.lespiau@xxxxxxxxx>
---
drivers/gpu/drm/i915/i915_dma.c | 18 +++++++++++++++++-
drivers/gpu/drm/i915/i915_reg.h | 1 +
2 files changed, 18 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
index 0f75d5c7..a95a1c0 100644
--- a/drivers/gpu/drm/i915/i915_dma.c
+++ b/drivers/gpu/drm/i915/i915_dma.c
@@ -1466,14 +1466,30 @@ static void i915_dump_device_info(struct drm_i915_private *dev_priv)
* - it's judged too laborious to fill n static structures with the limit
* when a simple if statement does the job,
* - run-time checks (eg read fuse/strap registers) are needed.
+ *
+ * This function needs to be called after the MMIO has been setup as we are
+ * reading registers, and before the first usage of the fields it can tweak.
*/
static void intel_device_info_runtime_init(struct drm_device *dev)
{
- struct intel_device_info *info = INTEL_INFO(dev);
+ struct drm_i915_private *dev_priv = dev->dev_private;
+ struct intel_device_info *info = &dev_priv->info;
info->num_planes = 1;
if (IS_VALLEYVIEW(dev))
info->num_planes = 2;
+
+ if ((INTEL_INFO(dev)->gen == 7 || INTEL_INFO(dev)->gen == 8) &&
+ !IS_VALLEYVIEW(dev)) {
+ u32 fuse_strap = I915_READ(FUSE_STRAP);
+ u32 sfuse_strap = I915_READ(SFUSE_STRAP);
+
+ if (fuse_strap & ILK_INTERNAL_DISPLAY_DISABLE ||
+ sfuse_strap & SFUSE_STRAP_DISPLAY_DISABLED) {
+ DRM_DEBUG_DRIVER("Display fused off, disabling\n");
+ info->num_pipes = 0;
+ }
+ }
}
/**
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index c6d9ba5..85e53ed 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -5411,6 +5411,7 @@
/* SFUSE_STRAP */
#define SFUSE_STRAP 0xc2014
+#define SFUSE_STRAP_DISPLAY_DISABLED (1<<7)
#define SFUSE_STRAP_DDIB_DETECTED (1<<2)
#define SFUSE_STRAP_DDIC_DETECTED (1<<1)
#define SFUSE_STRAP_DDID_DETECTED (1<<0)
--
1.8.3.1
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