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-rw-r--r--drivers/gpu/drm/i915/i915_drv.h2
-rw-r--r--drivers/gpu/drm/i915/i915_reg.h1
-rw-r--r--drivers/gpu/drm/i915/intel_crt.c8
-rw-r--r--drivers/gpu/drm/i915/intel_ddi.c2
4 files changed, 13 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 65213bc2f3c6..557843dd4b2e 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -915,6 +915,8 @@ typedef struct drm_i915_private {
bool hw_contexts_disabled;
uint32_t hw_context_size;
+ bool fdi_rx_polarity_reversed;
+
struct i915_suspend_saved_registers regfile;
/* Old dri1 support infrastructure, beware the dragons ya fools entering
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index acf768d0a5d1..3f75cfaf1c3f 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -3917,6 +3917,7 @@
#define FDI_FS_ERRC_ENABLE (1<<27)
#define FDI_FE_ERRC_ENABLE (1<<26)
#define FDI_DP_PORT_WIDTH_X8 (7<<19)
+#define FDI_RX_POLARITY_REVERSED_LPT (1<<16)
#define FDI_8BPC (0<<16)
#define FDI_10BPC (1<<16)
#define FDI_6BPC (2<<16)
diff --git a/drivers/gpu/drm/i915/intel_crt.c b/drivers/gpu/drm/i915/intel_crt.c
index 3084d018c740..fe20bf7e8d24 100644
--- a/drivers/gpu/drm/i915/intel_crt.c
+++ b/drivers/gpu/drm/i915/intel_crt.c
@@ -798,4 +798,12 @@ void intel_crt_init(struct drm_device *dev)
crt->force_hotplug_required = 0;
dev_priv->hotplug_supported_mask |= CRT_HOTPLUG_INT_STATUS;
+
+ /*
+ * TODO: find a proper way to discover whether we need to set the
+ * polarity reversal bit or not, instead of relying on the BIOS.
+ */
+ if (HAS_PCH_LPT(dev))
+ dev_priv->fdi_rx_polarity_reversed =
+ !!(I915_READ(_FDI_RXA_CTL) & FDI_RX_POLARITY_REVERSED_LPT);
}
diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
index 3264cb4564b0..4bad0f724019 100644
--- a/drivers/gpu/drm/i915/intel_ddi.c
+++ b/drivers/gpu/drm/i915/intel_ddi.c
@@ -180,6 +180,8 @@ void hsw_fdi_link_train(struct drm_crtc *crtc)
/* Enable the PCH Receiver FDI PLL */
rx_ctl_val = FDI_RX_PLL_ENABLE | FDI_RX_ENHANCE_FRAME_ENABLE |
((intel_crtc->fdi_lanes - 1) << 19);
+ if (dev_priv->fdi_rx_polarity_reversed)
+ rx_ctl_val |= FDI_RX_POLARITY_REVERSED_LPT;
I915_WRITE(_FDI_RXA_CTL, rx_ctl_val);
POSTING_READ(_FDI_RXA_CTL);
udelay(220);