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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 <damien.lespiau@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@gmail.com>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
This commit is contained in:
Damien Lespiau 2012-12-11 18:48:29 +00:00 committed by Daniel Vetter
parent fdfa175d0a
commit 3e68320ef8
4 changed files with 13 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
drivers/gpu/drm/i915/i915_drv.h
View File

@ -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;

2
drivers/gpu/drm/i915/i915_reg.h
View File

@ -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)

14
drivers/gpu/drm/i915/intel_crt.c
View File

@ -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;
}
}

6
drivers/gpu/drm/i915/intel_ddi.c
View File

@ -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);