From 3e68320ef84528604d971afc3cadfbe208bef001 Mon Sep 17 00:00:00 2001 From: Damien Lespiau Date: Tue, 11 Dec 2012 18:48:29 +0000 Subject: [PATCH] drm/i915: Preserve the FDI line reversal override bit on CPT The FDI link has supported link reversal to make the PCB layout engineer's life easier for quite a while and we have always presered this bit as we programmed FDI_RX_CTL with a read/modify/write sequence. We're trying to take a bit more control over what the BIOS leaves in various register and with the introduction of DDI, started to program FDI_RX_CTL fully. There's a fused bit to indicate DMI link reversal and FDI defaults to mirroring that configuration. We have a bit to override that behaviour that we need to preserve from the BIOS. Signed-off-by: Damien Lespiau Reviewed-by: Rodrigo Vivi Reviewed-by: Paulo Zanoni Cc: stable@vger.kernel.org Signed-off-by: Daniel Vetter --- drivers/gpu/drm/i915/i915_drv.h | 2 +- drivers/gpu/drm/i915/i915_reg.h | 2 +- drivers/gpu/drm/i915/intel_crt.c | 14 +++++++++----- drivers/gpu/drm/i915/intel_ddi.c | 6 ++---- 4 files changed, 13 insertions(+), 11 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h index b1f6a0925b5..e95337c9745 100644 --- a/drivers/gpu/drm/i915/i915_drv.h +++ b/drivers/gpu/drm/i915/i915_drv.h @@ -1040,7 +1040,7 @@ typedef struct drm_i915_private { bool hw_contexts_disabled; uint32_t hw_context_size; - bool fdi_rx_polarity_reversed; + u32 fdi_rx_config; struct i915_suspend_saved_registers regfile; diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h index d7542cd4abf..64919eee248 100644 --- a/drivers/gpu/drm/i915/i915_reg.h +++ b/drivers/gpu/drm/i915/i915_reg.h @@ -3911,7 +3911,7 @@ #define FDI_10BPC (1<<16) #define FDI_6BPC (2<<16) #define FDI_12BPC (3<<16) -#define FDI_LINK_REVERSE_OVERWRITE (1<<15) +#define FDI_RX_LINK_REVERSAL_OVERRIDE (1<<15) #define FDI_DMI_LINK_REVERSE_MASK (1<<14) #define FDI_RX_PLL_ENABLE (1<<13) #define FDI_FS_ERR_CORRECT_ENABLE (1<<11) diff --git a/drivers/gpu/drm/i915/intel_crt.c b/drivers/gpu/drm/i915/intel_crt.c index 68e79f32e10..cfc96878d74 100644 --- a/drivers/gpu/drm/i915/intel_crt.c +++ b/drivers/gpu/drm/i915/intel_crt.c @@ -801,10 +801,14 @@ void intel_crt_init(struct drm_device *dev) 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. + * TODO: find a proper way to discover whether we need to set the the + * polarity and link reversal bits 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); + if (HAS_PCH_LPT(dev)) { + u32 fdi_config = FDI_RX_POLARITY_REVERSED_LPT | + FDI_RX_LINK_REVERSAL_OVERRIDE; + + dev_priv->fdi_rx_config = I915_READ(_FDI_RXA_CTL) & fdi_config; + } } diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c index cedf4ab5ff1..89bdb1be61e 100644 --- a/drivers/gpu/drm/i915/intel_ddi.c +++ b/drivers/gpu/drm/i915/intel_ddi.c @@ -180,10 +180,8 @@ void hsw_fdi_link_train(struct drm_crtc *crtc) FDI_RX_TP1_TO_TP2_48 | FDI_RX_FDI_DELAY_90); /* 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; + rx_ctl_val = dev_priv->fdi_rx_config | FDI_RX_ENHANCE_FRAME_ENABLE | + FDI_RX_PLL_ENABLE | ((intel_crtc->fdi_lanes - 1) << 19); I915_WRITE(_FDI_RXA_CTL, rx_ctl_val); POSTING_READ(_FDI_RXA_CTL); udelay(220); -- 2.41.0