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drm/i915: Fix VLV PLL LPF coefficients for DAC

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The current PLL settings produce a rather unstable picture when
I hook up a VLV to my HP ZR24w display via a VGA cable.

According to VLV2A0_DP_eDP_HDMI_DPIO_driver_vbios_notes_9, we should
use the the same LPF coefficients for DAC as we do for HDMI and RBR DP.
And indeed that seems to cure the shivers.

v2: Add the name of the relevant document to the commit message

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
This commit is contained in:
Ville Syrjälä 2013-06-14 14:02:52 +03:00 committed by Daniel Vetter
parent 7425034a33
commit 99750bd46f
1 changed files with 1 additions and 0 deletions
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drivers/gpu/drm/i915/intel_display.c
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@ -4404,6 +4404,7 @@ static void vlv_update_pll(struct intel_crtc *crtc)
/* Set HBR and RBR LPF coefficients */
if (crtc->config.port_clock == 162000 ||
intel_pipe_has_type(&crtc->base, INTEL_OUTPUT_ANALOG) ||
intel_pipe_has_type(&crtc->base, INTEL_OUTPUT_HDMI))
vlv_dpio_write(dev_priv, DPIO_LFP_COEFF(pipe),
0x005f0021);