[Intel-gfx] [PATCH 16/36] drm/i915: try each voltage twice at hsw_fdi_link_train

[Daniel Vetter]

On Wed, Oct 31, 2012 at 06:12:35PM -0200, Paulo Zanoni wrote:
> From: Paulo Zanoni <paulo.r.zanoni at intel.com>
> 
> From the mode set sequence document: "Each setting should be tried at
> least twice before failing mode set".
> 
> Signed-off-by: Paulo Zanoni <paulo.r.zanoni at intel.com>
> ---
>  drivers/gpu/drm/i915/intel_ddi.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
> index f8ca3c4..94c6b76 100644
> --- a/drivers/gpu/drm/i915/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/intel_ddi.c
> @@ -179,7 +179,7 @@ void hsw_fdi_link_train(struct drm_crtc *crtc)
>  	I915_WRITE(PORT_CLK_SEL(PORT_E), intel_crtc->ddi_pll_sel);
>  
>  	/* Start the training iterating through available voltages and emphasis */
> -	for (i=0; i < ARRAY_SIZE(hsw_ddi_buf_ctl_values); i++) {
> +	for (i = 0; i < ARRAY_SIZE(hsw_ddi_buf_ctl_values) * 2; i++) {
>  		/* Configure DP_TP_CTL with auto-training */
>  		I915_WRITE(DP_TP_CTL(PORT_E),
>  					DP_TP_CTL_FDI_AUTOTRAIN |
> @@ -191,7 +191,7 @@ void hsw_fdi_link_train(struct drm_crtc *crtc)
>  		I915_WRITE(DDI_BUF_CTL(PORT_E),
>  			   DDI_BUF_CTL_ENABLE |
>  			   ((intel_crtc->fdi_lanes - 1) << 1) |
> -			   hsw_ddi_buf_ctl_values[i]);
> +			   hsw_ddi_buf_ctl_values[i >> 1]);

I think a simple / 2 is clearer here and symmetric with the * 2 above. The
compiler will apply clever tricks for you anyway ;-)
-Daniel

>  		POSTING_READ(DDI_BUF_CTL(PORT_E));
>  
>  		udelay(600);
> -- 
> 1.7.11.4
> 
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch