diff mbox

drm/i915: Fix VLV PLL LPF coefficients for DAC

Message ID 1371137855-8373-1-git-send-email-ville.syrjala@linux.intel.com (mailing list archive)
State New, archived
Headers show

Commit Message

Ville Syrjälä June 13, 2013, 3:37 p.m. UTC
From: Ville Syrjälä <ville.syrjala@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 some docs, 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.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
---
With this the hybrid PLL mode patch can be dropped.

 drivers/gpu/drm/i915/intel_display.c | 1 +
 1 file changed, 1 insertion(+)

Comments

Jesse Barnes June 13, 2013, 8:03 p.m. UTC | #1
On Thu, 13 Jun 2013 18:37:35 +0300
ville.syrjala@linux.intel.com wrote:

> From: Ville Syrjälä <ville.syrjala@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 some docs, 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.
> 
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> ---
> With this the hybrid PLL mode patch can be dropped.
> 
>  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);

I think it's ok, but can you specify the doc title in the commit
message?  Should make things easier to find in the rat's nest of files
later. :)
diff mbox

Patch

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);