[Intel-gfx] [PATCH] [VPG HSW-A] drm/i915: BUN vol4g[DevHSW]

[Biswas, KoushikX]

Hi Paulo,
There are some changes in voltage swing levels for Haswell platform. In current implementation, macro name are given after the swing values. But the values are changed for Haswell. This comment is added to avoid the confusion during signal level debug or other similar kind of activity.  


Thanks and regards,

Koushik

-----Original Message-----
From: Paulo Zanoni [mailto:przanoni at gmail.com] 
Sent: Tuesday, August 27, 2013 12:46 AM
To: Biswas, KoushikX
Cc: Intel Graphics Development
Subject: Re: [Intel-gfx] [PATCH] [VPG HSW-A] drm/i915: BUN vol4g[DevHSW]

2013/8/26 Koushik Biswas <koushikx.biswas at intel.com>:
> From: koushik <koushikx.biswas at intel.com>
>
> WW43 2012 - DDI buffer translation corrections
> WW36 2012 - Added HDMI voltage swing (not implemented
>                 for HDMI)
>
> Added comments with voltage swing, pre-emphasis, transition and 
> non-transition values in form of table for reference. This values are 
> applicable only for HSW platform.


But why exactly do we need this comment? We already have the
intel_hsw_signal_levels() function (inside intel_dp.c) which is basically the implementation of your comment.


>
> Signed-off-by: koushik <koushikx.biswas at intel.com>
> Change-Id: I0cff220c7d047f41b2a96b3e3880b4029550d458
> ---
>  drivers/gpu/drm/i915/intel_ddi.c |   31 +++++++++++++++++++++++++++++++
>  drivers/gpu/drm/i915/intel_dp.c  |   32 ++++++++++++++++++++++++++++++++
>  2 files changed, 63 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/intel_ddi.c 
> b/drivers/gpu/drm/i915/intel_ddi.c
> index 5131517..0de236e 100644
> --- a/drivers/gpu/drm/i915/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/intel_ddi.c
> @@ -128,6 +128,37 @@ void intel_prepare_ddi(struct drm_device *dev)
>         intel_prepare_ddi_buffers(dev, PORT_E, true);  }
>
> +
> +/* Updating the new table in comments as it doesn't cause any logic 
> +change */
> +
> +/************* For HSW Voltage swing levels 
> +***************************/ 
> +/********************************************************************
> +**/ 
> +/*___________________________________________________________________
> +_*/ /*|Entry|Voltage|Pre-emphasis|Non-Transition|Transition 
> +|Pre-emphasis|*/
> +/*|     |Swing  |level       |mV diff p-p   |mV diff p-p|db          |*/
> +/*|------------------------------------------------------------------|*/
> +/*|0    |0      |0           |400           |400        |0           |*/
> +/*|------------------------------------------------------------------|*/
> +/*|1    |0      |1           |400           |600        |3.5         |*/
> +/*|------------------------------------------------------------------|*/
> +/*|2    |0      |2           |400           |800        |6           |*/
> +/*|------------------------------------------------------------------|*/
> +/*|3    |0      |3           |400           |1000       |8           |*/
> +/*|------------------------------------------------------------------|*/
> +/*|4    |1      |0           |600           |600        |0           |*/
> +/*|------------------------------------------------------------------|*/
> +/*|5    |1      |1           |600           |900        |3.5         |*/
> +/*|------------------------------------------------------------------|*/
> +/*|6    |1      |2           |600           |1000       |4.5         |*/
> +/*|------------------------------------------------------------------|*/
> +/*|7    |2      |0           |800           |800        |0           |*/
> +/*|------------------------------------------------------------------|*/
> +/*|8    |2      |1           |1000          |1000       |2           |*/
> +/*|------------------------------------------------------------------|*/
> +/*|9    |       Entry 9 is only used for HDMI and DVI                |*/
> +/*|------------------------------------------------------------------
> +|*/ 
> +/********************************************************************
> +**/
> +
>  static const long hsw_ddi_buf_ctl_values[] = {
>         DDI_BUF_EMP_400MV_0DB_HSW,
>         DDI_BUF_EMP_400MV_3_5DB_HSW,
> diff --git a/drivers/gpu/drm/i915/intel_dp.c 
> b/drivers/gpu/drm/i915/intel_dp.c index 9fd7f90..fa73fb1 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -1809,6 +1809,38 @@ intel_gen7_edp_signal_levels(uint8_t train_set)
>         }
>  }
>
> +
> +/* Updating the new table in comments as it doesn't cause any logic 
> +change */
> +
> +/************* For HSW Voltage swing levels 
> +***************************/ 
> +/********************************************************************
> +**/ 
> +/*___________________________________________________________________
> +_*/ /*|Entry|Voltage|Pre-emphasis|Non-Transition|Transition 
> +|Pre-emphasis|*/
> +/*|     |Swing  |level       |mV diff p-p   |mV diff p-p|db          |*/
> +/*|------------------------------------------------------------------|*/
> +/*|0    |0      |0           |400           |400        |0           |*/
> +/*|------------------------------------------------------------------|*/
> +/*|1    |0      |1           |400           |600        |3.5         |*/
> +/*|------------------------------------------------------------------|*/
> +/*|2    |0      |2           |400           |800        |6           |*/
> +/*|------------------------------------------------------------------|*/
> +/*|3    |0      |3           |400           |1000       |8           |*/
> +/*|------------------------------------------------------------------|*/
> +/*|4    |1      |0           |600           |600        |0           |*/
> +/*|------------------------------------------------------------------|*/
> +/*|5    |1      |1           |600           |900        |3.5         |*/
> +/*|------------------------------------------------------------------|*/
> +/*|6    |1      |2           |600           |1000       |4.5         |*/
> +/*|------------------------------------------------------------------|*/
> +/*|7    |2      |0           |800           |800        |0           |*/
> +/*|------------------------------------------------------------------|*/
> +/*|8    |2      |1           |1000          |1000       |2           |*/
> +/*|------------------------------------------------------------------|*/
> +/*|9    |       Entry 9 is only used for HDMI and DVI                |*/
> +/*|------------------------------------------------------------------
> +|*/ 
> +/********************************************************************
> +**/
> +
> +
>  /* Gen7.5's (HSW) DP voltage swing and pre-emphasis control */  
> static uint32_t  intel_hsw_signal_levels(uint8_t train_set)
> --
> 1.7.9.5
>
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--
Paulo Zanoni