This is required for a stable FDI connection.
v2: fix and simplify the FDI_RX_MISC bits as noticed by Paulo Zanoni.
CC: Paulo Zanoni <paulo.r.zan...@intel.com>
Signed-off-by: Eugeni Dodonov <eugeni.dodo...@intel.com>
---
drivers/gpu/drm/i915/i915_reg.h | 3 +++
drivers/gpu/drm/i915/intel_ddi.c | 9 +++++++++
2 files changed, 12 insertions(+)
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 5b0c5f6..287d277 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -3849,6 +3849,9 @@
#define _FDI_RXA_TUSIZE2 0xf0038
#define _FDI_RXB_TUSIZE1 0xf1030
#define _FDI_RXB_TUSIZE2 0xf1038
+#define FDI_RX_TP1_TO_TP2_48 (2<<20)
+#define FDI_RX_TP1_TO_TP2_64 (3<<20)
+#define FDI_RX_FDI_DELAY_90 (0x90<<0)
#define FDI_RX_MISC(pipe) _PIPE(pipe, _FDI_RXA_MISC, _FDI_RXB_MISC)
#define FDI_RX_TUSIZE1(pipe) _PIPE(pipe, _FDI_RXA_TUSIZE1, _FDI_RXB_TUSIZE1)
#define FDI_RX_TUSIZE2(pipe) _PIPE(pipe, _FDI_RXA_TUSIZE2, _FDI_RXB_TUSIZE2)
diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
index effb263..2d5acd2 100644
--- a/drivers/gpu/drm/i915/intel_ddi.c
+++ b/drivers/gpu/drm/i915/intel_ddi.c
@@ -170,6 +170,15 @@ void hsw_fdi_link_train(struct drm_crtc *crtc)
udelay(600);
+ /* We need to program FDI_RX_MISC with the default TP1 to TP2
+ * values before enabling the receiver, and configure the delay
+ * for the FDI timing generator to 90h. Luckily, all the other
+ * bits are supposed to be zeroed, so we can write those values
+ * directly.
+ */
+ I915_WRITE(FDI_RX_MISC(pipe), FDI_RX_TP1_TO_TP2_48 |
+ FDI_RX_FDI_DELAY_90);
+
/* Enable CPU FDI Receiver with auto-training */
reg = FDI_RX_CTL(pipe);
I915_WRITE(reg,
--
1.7.11.1
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