[Intel-gfx] [PATCH 1/4] drm/i915: Gather the HDMI level shifter logic into one place

[Paulo Zanoni]

2014-08-01 7:07 GMT-03:00 Damien Lespiau <damien.lespiau at intel.com>:
> The knowledge about the HDMI/DVI DDI translation table was scattered
> around.
>   - info->hdmi_level_shift was initialized with 6, the index of the 800
>     mV, 0dB translation
>   - A check on the VBT value was done to ensure it wasn't overflowing
>     the translation table (< 0xC)
>   - The actual programming was done in intel_ddi.c
>
> As we need to change that knowledge for Broadwell, let's gather
> everything into one place.

Yeah, it's much better this way.
Reviewed-by: Paulo Zanoni <paulo.r.zanoni at intel.com>

>
> Signed-off-by: Damien Lespiau <damien.lespiau at intel.com>
> ---
>  drivers/gpu/drm/i915/i915_drv.h   |  6 ++++++
>  drivers/gpu/drm/i915/intel_bios.c | 13 +++++--------
>  drivers/gpu/drm/i915/intel_ddi.c  | 14 +++++++++++++-
>  3 files changed, 24 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index d604f4f..2e41616 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -1229,6 +1229,12 @@ enum modeset_restore {
>  };
>
>  struct ddi_vbt_port_info {
> +       /*
> +        * This is an index in the HDMI/DVI DDI buffer translation table.
> +        * The special value HDMI_LEVEL_SHIFT_UNKNOWN means the VBT didn't
> +        * populate this field.
> +        */
> +#define HDMI_LEVEL_SHIFT_UNKNOWN       0xff
>         uint8_t hdmi_level_shift;
>
>         uint8_t supports_dvi:1;
> diff --git a/drivers/gpu/drm/i915/intel_bios.c b/drivers/gpu/drm/i915/intel_bios.c
> index a669550..031c565 100644
> --- a/drivers/gpu/drm/i915/intel_bios.c
> +++ b/drivers/gpu/drm/i915/intel_bios.c
> @@ -976,12 +976,10 @@ static void parse_ddi_port(struct drm_i915_private *dev_priv, enum port port,
>         if (bdb->version >= 158) {
>                 /* The VBT HDMI level shift values match the table we have. */
>                 hdmi_level_shift = child->raw[7] & 0xF;
> -               if (hdmi_level_shift < 0xC) {
> -                       DRM_DEBUG_KMS("VBT HDMI level shift for port %c: %d\n",
> -                                     port_name(port),
> -                                     hdmi_level_shift);
> -                       info->hdmi_level_shift = hdmi_level_shift;
> -               }
> +               DRM_DEBUG_KMS("VBT HDMI level shift for port %c: %d\n",
> +                             port_name(port),
> +                             hdmi_level_shift);
> +               info->hdmi_level_shift = hdmi_level_shift;
>         }
>  }
>
> @@ -1114,8 +1112,7 @@ init_vbt_defaults(struct drm_i915_private *dev_priv)
>                 struct ddi_vbt_port_info *info =
>                         &dev_priv->vbt.ddi_port_info[port];
>
> -               /* Recommended BSpec default: 800mV 0dB. */
> -               info->hdmi_level_shift = 6;
> +               info->hdmi_level_shift = HDMI_LEVEL_SHIFT_UNKNOWN;
>
>                 info->supports_dvi = (port != PORT_A && port != PORT_E);
>                 info->supports_hdmi = info->supports_dvi;
> diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
> index a6024de..80e2a42 100644
> --- a/drivers/gpu/drm/i915/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/intel_ddi.c
> @@ -145,7 +145,7 @@ static void intel_prepare_ddi_buffers(struct drm_device *dev, enum port port)
>  {
>         struct drm_i915_private *dev_priv = dev->dev_private;
>         u32 reg;
> -       int i;
> +       int i, n_hdmi_entries, hdmi_800mV_0dB;
>         int hdmi_level = dev_priv->vbt.ddi_port_info[port].hdmi_level_shift;
>         const u32 *ddi_translations_fdi;
>         const u32 *ddi_translations_dp;
> @@ -156,15 +156,21 @@ static void intel_prepare_ddi_buffers(struct drm_device *dev, enum port port)
>                 ddi_translations_fdi = bdw_ddi_translations_fdi;
>                 ddi_translations_dp = bdw_ddi_translations_dp;
>                 ddi_translations_edp = bdw_ddi_translations_edp;
> +               n_hdmi_entries = ARRAY_SIZE(hsw_ddi_translations_hdmi);
> +               hdmi_800mV_0dB = 6;
>         } else if (IS_HASWELL(dev)) {
>                 ddi_translations_fdi = hsw_ddi_translations_fdi;
>                 ddi_translations_dp = hsw_ddi_translations_dp;
>                 ddi_translations_edp = hsw_ddi_translations_dp;
> +               n_hdmi_entries = ARRAY_SIZE(hsw_ddi_translations_hdmi);
> +               hdmi_800mV_0dB = 6;
>         } else {
>                 WARN(1, "ddi translation table missing\n");
>                 ddi_translations_edp = bdw_ddi_translations_dp;
>                 ddi_translations_fdi = bdw_ddi_translations_fdi;
>                 ddi_translations_dp = bdw_ddi_translations_dp;
> +               n_hdmi_entries = ARRAY_SIZE(hsw_ddi_translations_hdmi);
> +               hdmi_800mV_0dB = 6;
>         }
>
>         switch (port) {
> @@ -193,6 +199,12 @@ static void intel_prepare_ddi_buffers(struct drm_device *dev, enum port port)
>                 I915_WRITE(reg, ddi_translations[i]);
>                 reg += 4;
>         }
> +
> +       /* Choose a good default if VBT is badly populated */
> +       if (hdmi_level == HDMI_LEVEL_SHIFT_UNKNOWN ||
> +           hdmi_level >= n_hdmi_entries)
> +               hdmi_level = hdmi_800mV_0dB;
> +
>         /* Entry 9 is for HDMI: */
>         for (i = 0; i < 2; i++) {
>                 I915_WRITE(reg, hsw_ddi_translations_hdmi[hdmi_level * 2 + i]);
> --
> 1.8.3.1
>
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx at lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx



-- 
Paulo Zanoni