[Intel-gfx] [PATCH v2 1/2] drm/i915: Fix VLV PLL LPF coefficients for DAC

[ville.syrjala at linux.intel.com]

From: Ville Syrjälä <ville.syrjala at linux.intel.com>

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 at linux.intel.com>
---
 drivers/gpu/drm/i915/intel_display.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 29f2c0d..465d6bc 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -4405,6 +4405,7 @@ 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);
-- 
1.8.1.5