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| author | Paulo Zanoni <paulo.r.zanoni@intel.com> | 2012-12-01 15:04:26 +0100 |
|---|---|---|
| committer | Daniel Vetter <daniel.vetter@ffwll.ch> | 2012-12-10 11:14:29 +0100 |
| commit | 68d18ad7fbc16288aa230ec0ffb4416fd4363c87 (patch) | |
| tree | 24d670effc303e0f849480cdd872aeaabcfbae4a /drivers/gpu/drm/i915/intel_crt.c | |
| parent | drm/i915: add lpt_init_pch_refclk (diff) | |
| download | linux-68d18ad7fbc16288aa230ec0ffb4416fd4363c87.tar.xz linux-68d18ad7fbc16288aa230ec0ffb4416fd4363c87.zip | |
drm/i915: set the LPT FDI RX polarity reversal bit when needed
If we fail to set the bit when needed we get some nice FDI link
training failures (AKA "black screen on VGA output").
While we don't really know how to properly choose whether we need to
set the bit or not (VBT?), just read the initial value set by the BIOS
and store it for later usage.
Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Diffstat (limited to 'drivers/gpu/drm/i915/intel_crt.c')
| -rw-r--r-- | drivers/gpu/drm/i915/intel_crt.c | 8 |
1 files changed, 8 insertions, 0 deletions
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); } |