Re: [PATCH 2/2] drm/i915: Move Valleyview DP DPLL divisor calc to intel_dp_set_clock

[Jani Nikula <jani.nikula@linux.intel.com>]

[Okay, I missed Daniel's review, and noticed I hadn't actually hit send
on this one either... but here goes anyway...]

On Fri, 30 Aug 2013, Chon Ming Lee <chon.ming.lee@intel.com> wrote:
> For DP pll settings, there is only two golden configs.  Instead of running
> through the algorithm to determine it, hardcode the value and get it
> determine in intel_dp_set_clock.
>
> Signed-off-by: Chon Ming Lee <chon.ming.lee@intel.com>
> ---
>  drivers/gpu/drm/i915/intel_display.c |   22 ++++------------------
>  drivers/gpu/drm/i915/intel_dp.c      |   12 +++++++++++-
>  2 files changed, 15 insertions(+), 19 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index f526ea9..453fa16 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -339,19 +339,6 @@ static const intel_limit_t intel_limits_vlv_hdmi = {
>  		.p2_slow = 2, .p2_fast = 20 },
>  };
>  
> -static const intel_limit_t intel_limits_vlv_dp = {
> -	.dot = { .min = 25000, .max = 270000 },
> -	.vco = { .min = 4000000, .max = 6000000 },
> -	.n = { .min = 1, .max = 7 },
> -	.m = { .min = 22, .max = 450 },
> -	.m1 = { .min = 2, .max = 3 },
> -	.m2 = { .min = 11, .max = 156 },
> -	.p = { .min = 10, .max = 30 },
> -	.p1 = { .min = 1, .max = 3 },
> -	.p2 = { .dot_limit = 270000,
> -		.p2_slow = 2, .p2_fast = 20 },
> -};
> -
>  static const intel_limit_t *intel_ironlake_limit(struct drm_crtc *crtc,
>  						int refclk)
>  {
> @@ -414,10 +401,8 @@ static const intel_limit_t *intel_limit(struct drm_crtc *crtc, int refclk)
>  	} else if (IS_VALLEYVIEW(dev)) {
>  		if (intel_pipe_has_type(crtc, INTEL_OUTPUT_ANALOG))
>  			limit = &intel_limits_vlv_dac;
> -		else if (intel_pipe_has_type(crtc, INTEL_OUTPUT_HDMI))
> +		else 
>  			limit = &intel_limits_vlv_hdmi;
> -		else
> -			limit = &intel_limits_vlv_dp;
>  	} else if (!IS_GEN2(dev)) {
>  		if (intel_pipe_has_type(crtc, INTEL_OUTPUT_LVDS))
>  			limit = &intel_limits_i9xx_lvds;
> @@ -4889,15 +4874,16 @@ static int i9xx_crtc_mode_set(struct drm_crtc *crtc,
>  	}
>  
>  	refclk = i9xx_get_refclk(crtc, num_connectors);
> +		
> +	limit = intel_limit(crtc, refclk);

Did you move this here just to avoid the warning about uninitialized
limit? It's a bit ugly... but then again the the whole is_dsi vs. not is
rather ugly already. *shrug*.

>  
> -	if (!is_dsi) {
> +	if (!is_dsi && !intel_crtc->config.clock_set) {
>  		/*
>  		 * Returns a set of divisors for the desired target clock with
>  		 * the given refclk, or FALSE.  The returned values represent
>  		 * the clock equation: reflck * (5 * (m1 + 2) + (m2 + 2)) / (n +
>  		 * 2) / p1 / p2.
>  		 */
> -		limit = intel_limit(crtc, refclk);
>  		ok = dev_priv->display.find_dpll(limit, crtc,
>  						 intel_crtc->config.port_clock,
>  						 refclk, NULL, &clock);
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index ab8a5ff..89a2606 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -51,6 +51,10 @@ static const struct dp_link_dpll pch_dpll[] =
>  				{{ DP_LINK_BW_1_62, {1,12,9,2,10,0,0,0,0}},
>  				{ DP_LINK_BW_2_7,  {2,14,8,1,10,0,0,0,0}}};
>  
> +static const struct dp_link_dpll vlv_dpll[] =
> +				{{ DP_LINK_BW_1_62, {5,3,81,3,2,0,0,0,0}},
> +				{ DP_LINK_BW_2_7, {1,2,27,2,2,0,0,0,0}}};
> +
>  /**
>   * is_edp - is the given port attached to an eDP panel (either CPU or PCH)
>   * @intel_dp: DP struct
> @@ -683,7 +687,13 @@ intel_dp_set_clock(struct intel_encoder *encoder,
>  		}
>  		pipe_config->clock_set = true;
>  	} else if (IS_VALLEYVIEW(dev)) {
> -		/* FIXME: Need to figure out optimized DP clocks for vlv. */
> +		for(i = 0; i < sizeof(vlv_dpll) / sizeof(struct dp_link_dpll); i++) {
> +			if (link_bw == vlv_dpll[i].link_bw){ 
> +				pipe_config->dpll = vlv_dpll[i].dpll;
> +				break;
> +			}
> +		}
> +		pipe_config->clock_set = true;

You now have three similar loops in the function. A follow-up patch
could pick the table to use in the if branches, and have a single loop
at the end. You could handle the array size by having .link_bw = 0 in
the last entry as a stop condition, and using that as the fallback entry
too (see my review of patch 1 about unknown link_bw values).

BR,
Jani.


>  	}
>  }
>  
> -- 
> 1.7.7.6
>
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-- 
Jani Nikula, Intel Open Source Technology Center