[Intel-gfx] [PATCH 1/3] drm/i915: check the DDC and AUX bits of the VBT on DDI machines

[Rodrigo Vivi]

Reviewed-by: Rodrigo Vivi <rodrigo.vivi at gmail.com>

On Wed, Aug 28, 2013 at 12:45 PM, Paulo Zanoni <przanoni at gmail.com> wrote:
> From: Paulo Zanoni <paulo.r.zanoni at intel.com>
>
> Our code currently assumes that port X will use the DP AUX channel X
> and the DDC pin X. The VBT should tell us how things are mapped, so
> add some WARNs in case we discover our assumptions are wrong (or in
> case the VBT is just wrong, which is also perfectly possible).
>
> Why would someone wire port B to AUX C and DDC D?
>
> Signed-off-by: Paulo Zanoni <paulo.r.zanoni at intel.com>
> ---
>  drivers/gpu/drm/i915/intel_bios.c | 27 +++++++++++++++++++++++++++
>  1 file changed, 27 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/intel_bios.c b/drivers/gpu/drm/i915/intel_bios.c
> index 79bb651..a6700ab 100644
> --- a/drivers/gpu/drm/i915/intel_bios.c
> +++ b/drivers/gpu/drm/i915/intel_bios.c
> @@ -575,6 +575,8 @@ static void parse_ddi_port(struct drm_i915_private *dev_priv, enum port port,
>         struct ddi_vbt_port_info *info = &dev_priv->vbt.ddi_port_info[port];
>         uint8_t hdmi_level_shift;
>         int i, j;
> +       bool is_dvi, is_dp;
> +       uint8_t aux_channel;
>         int dvo_ports[][2] = {
>                 {0, 10}, {1, 7}, {2, 8}, {3, 9}, {6, /* Unused */ 0},
>         };
> @@ -598,6 +600,31 @@ static void parse_ddi_port(struct drm_i915_private *dev_priv, enum port port,
>         if (!child)
>                 return;
>
> +       aux_channel = child->raw[25];
> +
> +       is_dvi = child->common.device_type & (1 << 4);
> +       is_dp = child->common.device_type & (1 << 2);
> +
> +       if (is_dvi) {
> +               WARN(child->common.ddc_pin == 0x05 && port != PORT_B,
> +                    "Unexpected DDC pin for port B\n");
> +               WARN(child->common.ddc_pin == 0x04 && port != PORT_C,
> +                    "Unexpected DDC pin for port C\n");
> +               WARN(child->common.ddc_pin == 0x06 && port != PORT_D,
> +                    "Unexpected DDC pin for port D\n");
> +       }
> +
> +       if (is_dp) {
> +               WARN(aux_channel == 0x40 && port != PORT_A,
> +                    "Unexpected AUX channel for port A\n");
> +               WARN(aux_channel == 0x10 && port != PORT_B,
> +                    "Unexpected AUX channel for port B\n");
> +               WARN(aux_channel == 0x20 && port != PORT_C,
> +                    "Unexpected AUX channel for port C\n");
> +               WARN(aux_channel == 0x30 && port != PORT_D,
> +                    "Unexpected AUX channel for port D\n");
> +       }
> +
>         if (bdb->version >= 158) {
>                 /* The VBT HDMI level shift values match the table we have. */
>                 hdmi_level_shift = child->raw[7] & 0xF;
> --
> 1.8.1.2
>
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-- 
Rodrigo Vivi
Blog: http://blog.vivi.eng.br