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
v4: rebase on top of drm-nightly
use DRM_INFO() for the message telling display is fused off
try to read the FUSE_LOCK bit to determine if PCH display is disabled
Reviewed-by: Mika Kuoppala <mika.kuopp...@intel.com> (for v3)
Reviewed-by: Ville Syrjälä <ville.syrj...@linux.intel.com> (for v3)
Signed-off-by: Damien Lespiau <damien.lesp...@intel.com>
---
drivers/gpu/drm/i915/i915_dma.c | 31 ++++++++++++++++++++++++++++++-
drivers/gpu/drm/i915/i915_reg.h | 2 ++
2 files changed, 32 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
index e281298..283ace8 100644
--- a/drivers/gpu/drm/i915/i915_dma.c
+++ b/drivers/gpu/drm/i915/i915_dma.c
@@ -1466,16 +1466,45 @@ 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,
+ * - after the PCH has been detected,
+ * - before the first usage of the fields it can tweak.
*/
static void intel_device_info_runtime_init(struct drm_device *dev)
{
+ struct drm_i915_private *dev_priv = dev->dev_private;
struct intel_device_info *info;
- info = (struct intel_device_info *)&to_i915(dev)->info;
+ info = (struct intel_device_info *)&dev_priv->info;
info->num_sprites = 1;
if (IS_VALLEYVIEW(dev))
info->num_sprites = 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);
+
+ /*
+ * SFUSE_STRAP is supposed to have a bit signalling the display
+ * is fused off. Unfortunately it seems that, at least in
+ * certain cases, fused off display means that PCH display
+ * reads don't land anywhere. In that case, we read 0s.
+ *
+ * On CPT/PPT, we can detect this case as SFUSE_STRAP_FUSE_LOCK
+ * should be set when taking over after the firmware.
+ */
+ if (fuse_strap & ILK_INTERNAL_DISPLAY_DISABLE ||
+ sfuse_strap & SFUSE_STRAP_DISPLAY_DISABLED ||
+ (dev_priv->pch_type == PCH_CPT &&
+ !(sfuse_strap & SFUSE_STRAP_FUSE_LOCK))) {
+ DRM_INFO("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 50968ef..aa5cfd7 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -5433,6 +5433,8 @@
/* SFUSE_STRAP */
#define SFUSE_STRAP 0xc2014
+#define SFUSE_STRAP_FUSE_LOCK (1<<13)
+#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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