On Thu, 23 Apr 2020, Imre Deak <imre.deak@xxxxxxxxx> wrote:
> Using an AUX channel which by default belongs to a non-TypeC PHY won't
> work on a TypeC PHY, since - as a side-effect besides providing an AUX
> channel - the AUX channel power well affects power manangement specific
> to the TypeC subsystem. Using a TypeC AUX channel on a non-TypeC PHY
> would probably also cause problems, so for simplicity prevent both.
>
> This fixes at least an ICL-Y machine in CI, which has a buggy VBT
> setting AUX-B as an alternative channel for port C.
Is it a production machine? Not happy about adding stuff for pre-pro
machines with buggy VBT. It'll bite us later. It always has.
Also, hate to see VBT code call into intel_display.c (intel_phy_is_tc).
BR,
Jani.
>
> Signed-off-by: Imre Deak <imre.deak@xxxxxxxxx>
> ---
> drivers/gpu/drm/i915/display/intel_bios.c | 84 +++++++++++++++--------
> 1 file changed, 57 insertions(+), 27 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_bios.c b/drivers/gpu/drm/i915/display/intel_bios.c
> index 839124647202..10d463723d12 100644
> --- a/drivers/gpu/drm/i915/display/intel_bios.c
> +++ b/drivers/gpu/drm/i915/display/intel_bios.c
> @@ -1538,11 +1538,38 @@ static enum port get_port_by_aux_ch(struct drm_i915_private *i915, u8 aux_ch)
> return PORT_NONE;
> }
>
> +static enum aux_ch
> +intel_bios_port_info_aux_ch(const struct ddi_vbt_port_info *info)
> +{
> + switch (info->alternate_aux_channel) {
> + case DP_AUX_A:
> + return AUX_CH_A;
> + case DP_AUX_B:
> + return AUX_CH_B;
> + case DP_AUX_C:
> + return AUX_CH_C;
> + case DP_AUX_D:
> + return AUX_CH_D;
> + case DP_AUX_E:
> + return AUX_CH_E;
> + case DP_AUX_F:
> + return AUX_CH_F;
> + case DP_AUX_G:
> + return AUX_CH_G;
> + default:
> + MISSING_CASE(info->alternate_aux_channel);
> + return AUX_CH_A;
> + }
> +}
> +
> static void sanitize_aux_ch(struct drm_i915_private *dev_priv,
> enum port port)
> {
> struct ddi_vbt_port_info *info = &dev_priv->vbt.ddi_port_info[port];
> enum port p;
> + enum aux_ch aux_ch;
> + bool aux_is_tc;
> + bool phy_is_tc;
>
> if (!info->alternate_aux_channel)
> return;
> @@ -1571,6 +1598,35 @@ static void sanitize_aux_ch(struct drm_i915_private *dev_priv,
>
> info->supports_dp = false;
> info->alternate_aux_channel = 0;
> +
> + return;
> + }
> +
> + aux_ch = intel_bios_port_info_aux_ch(info);
> + /* The AUX CH -> default port is a 1:1 mapping. */
> + aux_is_tc = intel_phy_is_tc(dev_priv,
> + intel_port_to_phy(dev_priv,
> + (enum port)aux_ch));
> + phy_is_tc = intel_phy_is_tc(dev_priv,
> + intel_port_to_phy(dev_priv, port));
> + if (aux_is_tc != phy_is_tc) {
> + /*
> + * Using an AUX channel which by default belongs to a TypeC
> + * PHY can't be used for non-TypeC PHYs and vice-versa. The
> + * reason is that TypeC AUX power wells can only be enabled in
> + * the current TypeC mode of the PHY and have an effect on power
> + * management specific to the TypeC subsystem.
> + */
> + drm_dbg_kms(&dev_priv->drm,
> + "Port %c on a %s PHY is trying to use the %s AUX CH %c, "
> + "disabling DP support on this port.\n",
> + port_name(port),
> + phy_is_tc ? "TypeC" : "non-TypeC",
> + aux_is_tc ? "TypeC" : "non-TypeC",
> + aux_ch_name(aux_ch));
> +
> + info->supports_dp = false;
> + info->alternate_aux_channel = 0;
> }
> }
>
> @@ -2595,33 +2651,7 @@ enum aux_ch intel_bios_port_aux_ch(struct drm_i915_private *dev_priv,
> return aux_ch;
> }
>
> - switch (info->alternate_aux_channel) {
> - case DP_AUX_A:
> - aux_ch = AUX_CH_A;
> - break;
> - case DP_AUX_B:
> - aux_ch = AUX_CH_B;
> - break;
> - case DP_AUX_C:
> - aux_ch = AUX_CH_C;
> - break;
> - case DP_AUX_D:
> - aux_ch = AUX_CH_D;
> - break;
> - case DP_AUX_E:
> - aux_ch = AUX_CH_E;
> - break;
> - case DP_AUX_F:
> - aux_ch = AUX_CH_F;
> - break;
> - case DP_AUX_G:
> - aux_ch = AUX_CH_G;
> - break;
> - default:
> - MISSING_CASE(info->alternate_aux_channel);
> - aux_ch = AUX_CH_A;
> - break;
> - }
> + aux_ch = intel_bios_port_info_aux_ch(info);
>
> drm_dbg_kms(&dev_priv->drm, "using AUX %c for port %c (VBT)\n",
> aux_ch_name(aux_ch), port_name(port));
--
Jani Nikula, Intel Open Source Graphics Center
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