Re: [PATCH 2/3] drm/i915: Refactor translate_signal_level()

From: "Ville Syrjälä" <ville.syrjala@linux.intel.com>
To: intel-gfx@lists.freedesktop.org
Subject: Re: [PATCH 2/3] drm/i915: Refactor translate_signal_level()
Date: Thu, 23 Feb 2017 19:47:18 +0200	[thread overview]
Message-ID: <20170223174718.GW31595@intel.com> (raw)
In-Reply-To: <20170223174352.sot73s52pqt5u3hh@boom>

On Thu, Feb 23, 2017 at 07:43:52PM +0200, David Weinehall wrote:
> On Thu, Feb 23, 2017 at 07:35:06PM +0200, ville.syrjala@linux.intel.com wrote:
> > From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > 
> > Convert the big switch statement in translate_signal_level() into a neat
> > table. The table also serves as documentation for the translation
> > tables. We'll also have other uses for this table later on.
> > 
> > Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> 
> Reviewed-by: David Weinehall <david.weinehall@linux.intel.com>
> 
> > ---
> >  drivers/gpu/drm/i915/intel_ddi.c | 60 ++++++++++++++--------------------------
> >  1 file changed, 21 insertions(+), 39 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
> > index 5e4b0172810d..6f8e57f127e5 100644
> > --- a/drivers/gpu/drm/i915/intel_ddi.c
> > +++ b/drivers/gpu/drm/i915/intel_ddi.c
> > @@ -34,6 +34,19 @@ struct ddi_buf_trans {
> >  	u8 i_boost;	/* SKL: I_boost; valid: 0x0, 0x1, 0x3, 0x7 */
> >  };
> >  
> > +static const u8 index_to_dp_signal_levels[] = {
> > +	[0] = DP_TRAIN_VOLTAGE_SWING_LEVEL_0 | DP_TRAIN_PRE_EMPH_LEVEL_0,
> > +	[1] = DP_TRAIN_VOLTAGE_SWING_LEVEL_0 | DP_TRAIN_PRE_EMPH_LEVEL_1,
> > +	[2] = DP_TRAIN_VOLTAGE_SWING_LEVEL_0 | DP_TRAIN_PRE_EMPH_LEVEL_2,
> > +	[3] = DP_TRAIN_VOLTAGE_SWING_LEVEL_0 | DP_TRAIN_PRE_EMPH_LEVEL_3,
> > +	[4] = DP_TRAIN_VOLTAGE_SWING_LEVEL_1 | DP_TRAIN_PRE_EMPH_LEVEL_0,
> > +	[5] = DP_TRAIN_VOLTAGE_SWING_LEVEL_1 | DP_TRAIN_PRE_EMPH_LEVEL_1,
> > +	[6] = DP_TRAIN_VOLTAGE_SWING_LEVEL_1 | DP_TRAIN_PRE_EMPH_LEVEL_2,
> > +	[7] = DP_TRAIN_VOLTAGE_SWING_LEVEL_2 | DP_TRAIN_PRE_EMPH_LEVEL_0,
> > +	[8] = DP_TRAIN_VOLTAGE_SWING_LEVEL_2 | DP_TRAIN_PRE_EMPH_LEVEL_1,
> > +	[9] = DP_TRAIN_VOLTAGE_SWING_LEVEL_3 | DP_TRAIN_PRE_EMPH_LEVEL_0,
> > +};
> > +
> >  /* HDMI/DVI modes ignore everything but the last 2 items. So we share
> >   * them for both DP and FDI transports, allowing those ports to
> >   * automatically adapt to HDMI connections as well
> > @@ -1604,48 +1617,17 @@ static void bxt_ddi_vswing_sequence(struct drm_i915_private *dev_priv,
> >  
> >  static uint32_t translate_signal_level(int signal_levels)
> >  {
> > -	uint32_t level;
> > -
> > -	switch (signal_levels) {
> > -	default:
> > -		DRM_DEBUG_KMS("Unsupported voltage swing/pre-emphasis level: 0x%x\n",
> > -			      signal_levels);
> > -	case DP_TRAIN_VOLTAGE_SWING_LEVEL_0 | DP_TRAIN_PRE_EMPH_LEVEL_0:
> > -		level = 0;
> > -		break;
> > -	case DP_TRAIN_VOLTAGE_SWING_LEVEL_0 | DP_TRAIN_PRE_EMPH_LEVEL_1:
> > -		level = 1;
> > -		break;
> > -	case DP_TRAIN_VOLTAGE_SWING_LEVEL_0 | DP_TRAIN_PRE_EMPH_LEVEL_2:
> > -		level = 2;
> > -		break;
> > -	case DP_TRAIN_VOLTAGE_SWING_LEVEL_0 | DP_TRAIN_PRE_EMPH_LEVEL_3:
> > -		level = 3;
> > -		break;
> > -
> > -	case DP_TRAIN_VOLTAGE_SWING_LEVEL_1 | DP_TRAIN_PRE_EMPH_LEVEL_0:
> > -		level = 4;
> > -		break;
> > -	case DP_TRAIN_VOLTAGE_SWING_LEVEL_1 | DP_TRAIN_PRE_EMPH_LEVEL_1:
> > -		level = 5;
> > -		break;
> > -	case DP_TRAIN_VOLTAGE_SWING_LEVEL_1 | DP_TRAIN_PRE_EMPH_LEVEL_2:
> > -		level = 6;
> > -		break;
> > -
> > -	case DP_TRAIN_VOLTAGE_SWING_LEVEL_2 | DP_TRAIN_PRE_EMPH_LEVEL_0:
> > -		level = 7;
> > -		break;
> > -	case DP_TRAIN_VOLTAGE_SWING_LEVEL_2 | DP_TRAIN_PRE_EMPH_LEVEL_1:
> > -		level = 8;
> > -		break;
> > +	int i;
> >  
> > -	case DP_TRAIN_VOLTAGE_SWING_LEVEL_3 | DP_TRAIN_PRE_EMPH_LEVEL_0:
> > -		level = 9;
> > -		break;
> > +	for (i = 0; i <  ARRAY_SIZE(index_to_dp_signal_levels); i++) {
> 
> Superfluous space between < and ARRAY_SIZE.

Ack.

> 
> > +		if (index_to_dp_signal_levels[i] == signal_levels)
> > +			return i;
> >  	}
> >  
> > -	return level;
> > +	WARN(1, "Unsupported voltage swing/pre-emphasis level: 0x%x\n",
> > +	     signal_levels);
> > +
> > +	return 0;
> >  }
> >  
> >  uint32_t ddi_signal_levels(struct intel_dp *intel_dp)
> > -- 
> > 2.10.2
> > 
> > _______________________________________________
> > Intel-gfx mailing list
> > Intel-gfx@lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/intel-gfx

-- 
Ville Syrjälä
Intel OTC
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