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

[Jesse Barnes]

On Fri, 14 Jun 2013 14:02:52 +0300
ville.syrjala at linux.intel.com wrote:

> 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);

Reviewed-by: Jesse Barnes <jbarnes at virtuousgeek.org>

-- 
Jesse Barnes, Intel Open Source Technology Center