[Intel-gfx] [PATCH] drm/i915: Fix VLV DP RBR/HDMI/DAC PLL LPF coefficients

[Jesse Barnes]

On Fri,  5 Jul 2013 19:21:38 +0300
ville.syrjala at linux.intel.com wrote:

> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> 
> I just got confirmation that we're using some old values for the PLL
> LPF coefficients for DP RBR/HDMI/DAC on VLV. The
> VLV2A0_DP_eDP_HDMI_DPIO_driver_vbios_notes_9 document lists both values
> by mistake, and apparently we had picked the wrong one. Change the
> coefficients to the recommended values.
> 
> Changing the value doesn't appear to destabilize the VGA output picture
> even with my sensitive HP ZR24w display. Also HDMI output to my TV still
> works fine.
> 
> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> ---
>  drivers/gpu/drm/i915/intel_display.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index fc2af13..b423432 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -4448,7 +4448,7 @@ static void vlv_update_pll(struct intel_crtc *crtc)
>  	    intel_pipe_has_type(&crtc->base, INTEL_OUTPUT_ANALOG) ||
>  	    intel_pipe_has_type(&crtc->base, INTEL_OUTPUT_HDMI))
>  		vlv_dpio_write(dev_priv, DPIO_LPF_COEFF(pipe),
> -				 0x005f0021);
> +				 0x009f0003);
>  	else
>  		vlv_dpio_write(dev_priv, DPIO_LPF_COEFF(pipe),
>  				 0x00d0000f);

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

-- 
Jesse Barnes, Intel Open Source Technology Center